Crewdroog: lol omg that DIY link was great though, I found one very very close to what i was gonna build!
The combos should be selected to work together, so you don't have to do a lot of outside checking; To be honest what cards/hardware is compatible with what machines, which CPU type it is, etc etc, i haven't kept up in years.
If you find a DIY package that suits you then i'd say go for it. Again make sure the power supply is strong enough for an upcoming video card. Double check it has everything you need. If you need an extra hard drive, video card, more ram, etc.
As a reminder, if you're not going to be gaming, one of the cheaper refurbished ones would probably suit you. However for gaming, well i've once gone with a bare-bones system of $125, and added a video card and hard drive and ram and it was good to go (
back in 2005, i could play Oblivion afterall :P).
edit: Oh yes just remembered.. In all likelihood a DIY system will most likely
***NOT*** include an OS. So you'll probably end up installing one you already own, or a Free OS... As i don't recommend Windows 8 or 10, your choices are probably having an old copy (
XP 64bit or Win7), acquiring a copy (
probably pirated), or using a variant of Linux. Linux GPU support has never been that high with NVidia so keep that in mind as well.