I would recommend getting the regular Denon D7000 first to see if you like the sound. The D7000 can be had for around $600US and it has a lot of bass. The lawton modded D7000 from what i read is great sounding but for someone just started in Head-fi, it might be a wiser investment to begin with the stock D7000 and then move up to the LA7000 (the cost of full LA7000 mod can probably buy you another pair of D7000) . My W3000ANV is still in transit but from what i read, the sound signature is quite different than the D7000, the W3000ANV seems to be good in vocals and not that strong in bass, one Head-fier mentioned the W3000ANV is like a closed version of HD800 (which i have as well, its excellent). I believe D7000 is good for bass/pop/ techno/electronic type of music in my opinion. W3000ANV for female vocals
I used the HD800 and D7000 for gaming in Battlefield 3, they are both excellent in producing the position of players and where people are shooting from, the HD800 will lack the oomph you might want in games for the explosions, the D7000 i believe is better for gaming.
If you are into bass/pop/rock type of music where its more enjoyable with more bass impact, i would recommend going for the D7000 as the price is very good currently (<$600US). And you can look at Audeze LCD2 ($995US, used < $850) as well and the new Fostex TH900 ($1970US, i am not too sure its worth the price tag)
And if you like W3000ANV($999new) sound signature, i believe you can look at Beyerdynamic T1, HD800 (an excellent all rounder) as well
However, just as Zarim said you will need a good DAC+AMP for these headphones to bring out their full potential .
If you are looking for a starter DAC/AMP that is very good in terms of $ / performance i would recommend trying the Nuforce Icon HDP, I had one for half a year with an LCD2 and it was excellent sounding. It should cost around $400 new or $300ish used on here.
Hope that helps.