The stock cooler that ships with the i7's are actually fairly decent. I built some CAD work stations and used stock coolers and overclock at stock voltage to 4 GHz. The stock coolers are silent (if you set to silent profile in BIOS) and only rev up when under heavy load.
With no OCing there is no reason not to get the stock cooler. Unless you are looking for something totally silent and want a passive cooler. Outside of that, no reason to spend more on some aftermarket cooler. If you don't have an OEM one, you can find them all day long on ebay for $8 and under new. Probably more than a few people here that would give you one free if you lived close.
Outside of that I think CM has the....T2? It's a 92mm tower cooler, nothing special, but better than the stocker and goes on sale for $10. Normal price being in the $15-17 range.