aright sorry I'm lazy haven't read whats been said
Get a 3200+ venice not a 3500+, it'll overclock to generally 2.8GHz on air and not necessarily stock voltage, but still low voltage and cool temps.
$100 for a good OC'ing motherboard is WAY too cheap, don't skimp out on this, this is after all the MOTHER board, which denotes it kind of handles your whole system.
You'd be good with a DFI Ultra-D
These boards have 2 PCI-E slots and a few PCI slots, so as been said yes a normal PCI card will work but as I'm sure you're aware of PCI cards suck
Patriot XBL ram is a good set of TCCD RAM that will overclock nicely and isn't quite as expensive as some other things like GSkill LA's but I heard the OCZ Platinum Rev 2's are sitting at $199
can OC too and are quite cheap, but need a lot of voltage which the DFI Ultra-D board will have no problem giving since it can give up to 4v, but really anything beyond 3.7 doesn't make a difference and when running that high voltage you DEFINITELY have to have a fan blowing on the RAM.
I wouldn't suggest quite going that high for every day use though. 3.3 would be enough for nice OC's while remaining fairly cool but I'd still use a fan.
Yeah that's about it