I would like to explain how my view makes me see that, "It's not just desire alone... but desire to act on it that makes desire lust."

The word translated "lust" in these passages has been rightly interpreted by JohnQ. And I agree with Blackstone that context is vitally important. The idea of "strong desire" is of itsef neither good nor bad. The same word, in these passages translated "lust" is also used of Jesus in the gospels where he said of the Jews, "with strong desire I wanted to gather you as a hen gathers her chicks under her wing, but you were unwilling". The NIV translation of this word in James 1 as "evil desire" is prejudicial I feel, they are borrowing from the context and I think perhaps wrongly. Jame's point that desire entices and leads away, concieves and THEN gives birth to sin, does not mean that the starting desire was sinful. If there is no leading away... the desire itself is neutral I'd think.

I will illustrate my point using the passages Blackstone listed.

Numbers 15:39
You will have these tassels to look at and so you will remember all the commands of the LORD, that you may obey them and not prostitute yourselves by going after the lusts of your own hearts and eyes.

In this passage the "going after" is significant. Not only is there desire in the hearts and eyes, but it is desire that has moved from mere admiration into coveting the thing desired. The eye has seen something desirable (so far no lust)... but then it begins to covet having it and lust is born.
To put my idea into a practical situation, let's say I see someone I find sexually attractive. I see them and immediately feel sexual desire for them (to me this is NOT lust). I look at them and say... "wow, how sexy and beautiful that person is... that is just the kind of person I'd like to have sex with" (to me this is still not lust). Then I go and think, "maybe if I go over there and talk to them I may have a chance to flirt with them". Now my desire has enticed me and is starting to draw me away from holiness. It has become lust. I could go further and be thinking, "if I could just get alone with that person I could make a play for them, try and get them into a sexual situation". Now my lust is really coveting and I have to be careful not to go after it.
Of course in the real world my actions would probably move slower and more sublty than this stark example... but I think my point is clear enough.

Job 31:1
"I made a covenant with my eyes not to look lustfully at a girl.

Important to note this passage doesn't say, "not to look" but "not to look lustfully. I have heard it suggested that, "as soon as a guy sees someone he finds attractive he should divert his eyes away" and to me that seems both extreme and ridiculous.
What then is looking lustfully? I use my same argument from the above passage. It is looking with covetous intent... looking with desire to act.... to take... to posess.
If I'm invited to a feast and all my favourite foods are laid out on the table, I may help myself as I please and my desire to have the foods there is perfectly holy and acceptable. However, once I am full any ongoing desire I have to keep eating for the sake of enjoying the food becomes greedy and therefore lustful. If I partake from the same food at the same table once again my motive has gone from something natural and holy to something corrupt. I have to stop looking lustfully at the food. The first time I looked it wasn't lustful.... it only becomes lustful looking when I want to take more than what is rightfully mine.
When Job made this point he surely wasn't including his wife. He can look at her all he wants and think about how much he intends to try and sex her. The desire itself is not sinful.
When Job looks at some other girl he finds hot, he can acknowledge that to himself, no problem. Then he must turn his heart homewards and say, but she is not mine to take as I please. His covenant kicks in... he shan't look at her and get drawn away by his desire to start visualising ways to make sex with this girl actually happen.

Proverbs 6:25
Do not lust in your heart after her beauty or let her captivate you with her eyes

This passage is talking about resisting the invitaitons of a prostitue or adulteress. Sure she's hot and sure you may want to go in and have a go with her.... but don't let your heart hunger to actually go there and do it. A man is in trouble once he begins hungering to take action.
One fellow would see this prostitue and say... "wow she's sexy and yeah I want to bed her, but I wouldn't dream of going anywhere near her, talk about trouble". He walks away without lust and unharmed.
Another fellow sees the same prostitued and says... "wow she's sexy, I want her.. I really want to go there and have her... how can I sneak in there and be with her.... there might be a way of doing it without my wife finding out.... etc.."
Whether he ever ends up going to her or not this second fellow is lusting in his heart and the first fellow is not.

Jeremiah 5:8
They are well-fed, lusty stallions, each neighing for another man's wife.

and
Jeremiah 13:27
your adulteries and lustful neighings, your shameless prostitution! I have seen your detestable acts on the hills and in the fields. Woe to you, O Jerusalem! How long will you be unclean?"

A lusty stallion here is calling out ...making a noise to attract the attention of the mare or possibly to challenge the competing males to a fight... or maybe he's just boasting about how hot he is... the conquering sex god ready to mount whomever he pleases.... seems like action to me. Either way, both these passages speak of unrestrained and indulgent desire. What these fellows want... they go after.


Ezekiel 16:26
You engaged in prostitution with the Egyptians, your lustful neighbors, and provoked me to anger with your increasing promiscuity.

Clearly lust here is desire actioned.

Ezekiel 20:24
because they had not obeyed my laws but had rejected my decrees and desecrated my Sabbaths, and their eyes lusted after their fathers' idols.

Lust here is "coveted to actually have". I read someone puttting it like this, "when I think about going to the mall, I'm not just enjoying a pleasent daydream of the joys of shopping, I'm actaully planning when I might go there and what I might purchase when I get there".

Matthew 5:28
But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart.

See my note on the Job passage.
The man here is not admiring her sexyness. He's not even using a remembered image of her in a masturbation fantasy. He's looking and thinking of how he may get her into an actual sexual situation. Since, in the greek, the verb in this sentence is passive that means he's looking so that she lusts. He's flirting or being sexually suggestive. He has not just desire... but intent to act.

Romans 1:26
Because of this, God gave them over to shameful lusts. Even their women exchanged natural relations for unnatural ones.

Romans 1:27
In the same way the men also abandoned natural relations with women and were inflamed with lust for one another. Men committed indecent acts with other men, and received in themselves the due penalty for their perversion.

Both verses clearly unite lusting to acting.

Hope that clarifies my position.
Blessings
Cat.