probably Dell (from the sound of it)
my knowlege comes from building my own computer.
did a lot of reading and research to make sure everything would work together (and to get some fairly good parts in it too)
based on your needs, I'd definately get a dual-core cpu (Athlon 64 X2's are still good)
for video card (I guess ATI is on top when it comes to performance/gaming)
I'd look into something inbetween RadeonX1600 and RadeonX1900
Nvidia still has some good stuff (usually a bit cheaper I think), if you go with that, look at the GeForce 7k line
You'll probably need a power supply rated for at least 400W (modular cabling is nice, but not a requirement...same with a big fan (>=120mm) and dual 12v rails, but I would consider the last two more important)
http://www.tigerdirect.com/applications ... &CatId=106
Ultra has satisfied me...plus it's got all those nice features for a reasonable price :up (flexforce cables are also nice. very easy to tuck away somewhere in the case...imporves airflow)
Get a mobo with Sata, at least one pci-e x16 (two if you think you might want to utilize sli/crossfire in the future...assuming that the tech becomes more widely used. Right now, sli/crossfire would be a waste of your money) and possibly raid capabilities (Raid 0/1 are the basics...0+1/5 and others are nice options to have though)
get some decent ram (ddr if possible...but this may just be my personal preference)
look for cas latency 2, or 2-2-2-5 (best possible timings)
2.5-3-3-7 is still good (my laptop runs 1GB (2x512) ddr SoDIMM at 333MHz with these timings...got each stick for about $35)
anything with cas 3 or higher can pretty much be left unconsidered
DDR2 doesn't start to outperform DDR until you reach 667MHz (pc5400)
and even then, pc5400 only offers miniscule improvement over pc3200
Sata hard drives offer faster data transfer as well as smaller, more flexible cables (also helps with airflow)
I'd invest in some decent speakers. Klipsch, Logitech and Creative are good names.
LCD monitors are nice, but they only work really well at specific resolutions (usually the native or max resloution)
300 cd/m is good for brightness (I had to turn mine down)
500:1 contrast ratio is normal (for now), but higher is better
dot pitch of .294mm is normal, lower is better (gives you a sharper picture...usually)
go with name brands for this (LG, Samsung, Sony, Viewsonic, HP, etc)
and don't forget the all important floppy-disk drive (stupid win XP can't read drivers from cd's during installation)