No AGP card will fit into a PCI-E slot. U need a bridge for that purpose. If ur not interested in buying a PCI-E gfx card, then go for an AGP based mobo.
875 vs 865? Hmm..the 865 is an excellent value+performance combo and is very very popular. Dunno about 875.
If ur thinking abt buying a PCI-E card however, well the ones currently out on the Indian market are just AGP cards with a bridge, so it doesn't really make sense to go for one right now. The GeForce 6600 would be coming soon (or it mite have come already and I dunno) to the Indian market, though its price here would definitely be much higher than its international (read US) price of $199.
I doubt if
proper PCI-E versions of cards like the 6800 have come out yet...but neway they will be waaaaaayyyy too costly.
Looks like AGP would be the better option.
Unless u plan to wait till 2005....