Should I get the New Vegas Series for the Xbox or PC? I'm not totally sure because if you get it for the PC you can do mods but then the computer wears down and for the Xbox you can't really do anything like make your own maps and such. I'm really on the verge of buying the computer game but I'm thinking about how much it would cost in the long run (Getting computer upgrade and other things). Are there any other things I should be concerned about either the Xbox 360 or PC?
I've played it on both, more on the PC, but I put about 4 hours into the 360 version as well. My thoughts, without slamming one platform or the other:
It depends a lot on your PC specs, you can have the fastest system in the world, but if you're sitting on a GTS250 or some low end 3D card, it's gonna run like ass. If you have the overall PC specs to run it, the PC version of the game is going to look a lot better and allow you to do things through mods and tweaking that you will never be able to do on the 360. Of course, you may not care about those things, and that's fine too. The 360 version still looks good (as good as a game running on an engine that is quickly approaching a decade old can look at least) and controls great. You'll also be the first to get the DLC coming out in December if that's something you're interested in.
If you are interested in mods, the number of New Vegas specific mods are ramping up at falloutnexus.com, it's pretty crazy how many there already are, but I guess of that has to do with most of them just being ported over to Fallout 3 to New Vegas.
It does use Steam. I personally have zero issues with Steam, it's always been pretty much 100% transparent for me when I game, and I have well over 200 games in my Steam account right now. I don't know anyone personally who uses it that has problems with it either, it's gotten to the point that if I can buy a game on Steam, I usually just don't buy it until I can. I set up a 1TB drive just for my Steam directory, and right now that directory is sitting at right at 450GB.
Both platforms are going to give you a great experience once the bugs are ironed out. Jeff at Giantbomb reported the game crashed on him a dozen times in 36 hours on the 360, I've had it crash twice on me in 7 hours, but both of those crashes were in the first 2 hours and I haven't had a problem since. It crashed on me 2 times in the 4 hours I played on the 360 as well, so obviously it's pretty busted across the board in some respects.
Whatever you decide to get it on, enjoy.