Choosing a CPU: i5, i7. 1156, 1366...

[taltamir]

due to lack of competition, intel's prices are obscene... as such this is the only worthwhile choice:
Intel Core i5-750 Lynnfield 2.66GHz 8MB L3 Cache LGA 1156 95W Quad-Core Processor - Retail
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115215
for a desktop unless you swim in money.

the i3 are cheaper... but for 35% less money you lose turbo boost AND half your cores... and get stuck with a dual core (in 2010? shudder).
if you are that strapped for cash, get an AMD athlon 2 quad core for 100$ instead.

So your choices are (for the sane non super wealthy extravagant individual)
@100$: AMD athlon II quad core
@200$: intel i5-750

There is NOTHING worthwhile above or below those two chips for the desktop at the moment...

PS: for a laptop the only acceptable choice is the cheapest i3 arrandale you can find.

 

[jinduy]

from glancing at intel's way of marketing, isn't it a no brainer that the i7 will perform faster than the i5 and the i5 will perform faster than the i3?

 

[MrK6]

from glancing at intel's way of marketing, isn't it a no brainer that the i7 will perform faster than the i5 and the i5 will perform faster than the i3?

Considering only one socket type, that's a reasonable statement. Across socket types, the lines start to blur and that statement becomes more application dependent.