Do the i5 and i7 cpus require different LGA sockets on the motherboard. It seems the i5 is a good buy, but possibly uses a LGA1156 socket, versus many i7 proccesors to chose from that use a LGA1366 socket. Is my understandin correct? i5 Motherbords are dead an not upgradable, while i7 MOBO's are have a wider selection of cpu's? I build my own pc's here at the house for a dozen years, and I'm trying to catch up, as it's been 3 years since the last upgrade.
All i5 chips are LGA1156.
i7 chips are LGA1366 except there is an LGA1156 model as well (think its the i7 860).
i9 will be coming out on LGA1366 at some stage.
Neither chipset has a wide selection of CPUs, but the 1366 is the only one with a new promised CPU in the works. Both chipsets will have newer processors, but 1156 is focused on the average mainstream user, and 1366 for the high end market.
775 is the one with lots of options, but it's a dead socket (its replacement is the 1156 in Intel's plan).