Ok, I hope this helps :D
Some brands you shouldn't get because they're bad is: Emachines (THE WORST THING EVER LAGS ON EVERYTHING!), Acer, Compaq, or Gateway
Gateway and Compaq aren't THAT bad, but they're not that great.
Some good brands you should seek are Mac's (They're a little pricey, but they're good, I recommend a dell), Dell (One of the best computer brands, but don't think about getting a extended warranty, HORRIBLE help and support center, getting an extended warranty is just a waste of money.), HP (The support is good, and the computers are pretty reliable, but not as reliable as dell or Macs, but overall they're pretty good.)
Those are the 3 good brands you should seek :D
But overall the best for performance is Mac books, but they're kind of pricey, if you're on a budget, I wouldn't fully recommend it if you are on a budget. The costumer support is very good, trust me, you can chat with a professional, and they help you. Dells are very good computers, one of the best besides Macs, but the problem about Dell is that they're kinda expensive, and also the Costumer Support is horrible. But they're good computers, so they don't break that easily, so you don't really need good costumer support, you know what I mean :). Hp's are pretty reliable, not as good as Dell's, but still good, and at least their costumer support is good!
Here are some computers from the 3 recommended companies that are good:
Mac
* 13-inch. Starts at $1199.
* 15-inch. Starts at $1699.
* 17-inch. Starts at $2499.
That's for mac book pro, and mac book pros are FAST and RELIABLE :), a lot of college students have it, and they LOVE it, and if you get a mac book for the summer, you get a FREE and I'm talking free ipod touch! :) So, I recommend a mac book pro if you're not on a budget. Mac books are good, but not as good as Mac book pro.
If you want the price mac books are, Starting at $999.
and here's the apple website if you want to check it out:
http://www.apple.com/
and here's the mac website:
http://www.apple.com/mac/
Then lets move on to dell.!.
BAD COSTUMER SUPPORT!!! That's a BIG thing here, if you like good costumer support, then get a dell. But if you don't care, I recommend a dell. I have a dell my self that runs on Vista 32, Vostro 220.
The xps's are EXTREME gaming, and they're very good, but if you game extreme like I mean SUPER extreme, then get one of these:
http://www.dell.com/us/en/home/desktops/desktop-studioxps-435mt/pd.aspx?refid=desktop-studioxps-435mt&s=dhs&cs=19
The pros about xps's is that it has the FASTEST core that I know of, and yes, it's better than quad, it's I7!!!! But, the i7, is mostly for EXTREME gaming, and they're kinda expensive, so if you multitask, a 2 duo would work, not an i7, and the 2 duo core, which I have, it's good for some gaming, and i7 is for EXTREME gaming, so a 2 duo would work, but if you want to have fun and get an i7, get one :D
http://configure.us.dell.com/dellstore/config.aspx?oc=dddota3&c=us&l=en&s=dhs&cs=19&kc=desktops_great_deals
This computer is rated 5 stars, and it's x4 phenomenon quad core, again, for extreme gaming, but if you want to have fun, its only 450$, a GOOD deal for just desktop. NOTE: THERE IS NO MEDIA CARD READER!!!
But that computer is for extreme gaming, and it's an AMAZING DEAL FOR THE PRICE!
You'll need to get a widescreen moniter, and they're about 150$+
seek for deals on moniters.
You should get your dell online, because ITS WAY BETTER IF YOU GET IT ONLINE!!! I got mine online.
http://configure.us.dell.com/dellstore/config.aspx?oc=dddoma4&c=us&l=en&s=dhs&cs=19&kc=desktops_great_deals
This one is another good deal, even though its another quad, it's still a very good pc! And, it's a good deal too!
Here's the dell website if you want to check the things out:
http://www.dell.com/
Hp's
http://welcome.hp.com/country/us/en/welcome.html#Product
You can look through all of them
The core 2 duo is good enough for you :)
The hard drive 320gb-500gb
The windows Vista Home premium, or Ultimate, but home premium is good enough
32 or 64 bit is fine
The memory: at least 2 gb to run vista!
LOL
Yeah, and I hope this helped, and I'm not a computer expert, I just know all these things, lol
THIS TOOK ME A WHILE TO ANSWER, SO YEAH