I would wait until system specs come out before buying. That said, if you want to get something now and you don't want to build your own rig, just make sure you're not bottlenecking yourself anywhere. I only have a non-gaming laptop with an APU, and I can tell you it runs TOR just fine. Oh, and I'd also get a copy of Windows 7. It's easier to deal with compatibility issues on an OS people have anolyzed half to death already. But really, if you want a gaming rig you might as well go the entire way, because otherwise your rig will be obsolete pretty fast. Also, I recommend Tom's Hardware. It's a good site with lots of knowledgeable, helpful people.
Recommended specs:
~600W+ power supply
1GB+ dedicated graphics (Nvidia has better graphics support, so they're more commonly used despite being more expensive)
2-4 core CPU @ 3.0Ghz or above, preferably overclockable (it will decrease your CPU shelf life but you won't be using it for more than 7 yrs anyway) (and also you won't need more than 2 cores for now because games haven't been developed to take advantage of that yet) (#cores > clock speed for performance, in general) (make sure your CPU won't catch fire because seriously not cool) (if you see a model with an i5 and better clock speed/same #cores take it the i7 is mostly better only for video editing anyways)
lots of fans and cooling (seriously, the last thing you want is for your rig to catch fire. It's not fun. Trust me.)
decent motherboard, preferably upgradeable (people tell me that if you check the specs your mobo should roughly equal the price of your CPU, but I think it's a bit rubbish. Secondary opinions welcome) (check to see which slots you've got) (and what you can plug in) (because PS2 mice/keyboards) (and stuff)
~8Gb RAM (some modern games don't even support that much RAM, and older games will have an issue with that)
smaller SSD (~64Gb?) to run Windows and your games on, larger HDD for storage because trust me, the extra SSD speed can make a difference but if it comes to that just get an HDD
good screen (seriously, a good graphics card is nigh-useless if you don't have a proper screen to view it on. Get a proper 1366x??? or above with HD, or you really won't be able to tell any difference.)
Parts you want to be really good: (aka. this is the most expensive and least upgradeable)
graphics card
CPU
motherboard
Random advice:
DDR3 is really fast no matter your clock speed
higher numbers on gbus generally better
USB 3.0 is great
I wouldn't go with choice #1 because [censored] power supply
Or with #3 because AMD CPUs run at slightly different clock speeds and they might try to lock you out of your BIOS, which can be bad and also they have less support than Nvidia and I'm running an AMD CPU right now and it really hates my games (no srsly, there's just a lot more that can glitch, and fewer things that will be patched)
#2 also has an AMD cpu well [censored]
maybe go with #1 and upgrade? ok you might have to upgrade a lot
but seriously, I'd recommend waiting and upgrading your computer budget
it will be worth it because a good rig will last you many years
Good luck!