I've done plenty of playthroughs of FO:NV on the Xbox 360 which all have been great and I've loved every second of it. So my question to you PC players out there is it worth getting a second copy of this game for the PC? I've generally heard that 3 has better mods than NV does. And I realize I could look up available mods, but I want actual feedback as to what everyone thinks of the mods. Are the available mods worth purchasing the game over again? Or are they mostly little tweaks that hardly change or expand upon the game?

http://www.youtube.com/user/AlChestBreach

-LITERALLY- a Youtube channel dedicated to reviewing New Vegas mods. Entertaining too.
You could thumb through his uploads to see how many mods he's reviewed. I myself am not a big fan of mods, but I'd suggest checking out the Chryslus Corvega mod vids he has (the mod is in french but provides english subtitles) and imo, that's the most well-done mod I've seen him review. There's definitely plenty (Project Nevada, Willow and New Vegas Bounties probably being the most well-known ones, and again the channel I linked has reviewed them all), and while it's definitely hard to compare the quality of mods for FO3 and mods for NV, I'd say they both have plenty. If you enjoy New Vegas more then yeah, should probably stick to it.