I'll be overclocking a C2D E4500 on a gigabyte P35-DS3L, was originally going to go after the value ram (Gskill, adata etc). However now I've seen a lot of people standing firmly by crucial ballistix, kingston hyperx, and corsair xms2's. Any recommendations? Are all 3 pretty equivalent?

Any DDR2-800 will be fine.
The E4500 has a default FSB of 800.

You need MUCH faster RAM to OC the new FSB1333 chips.
Some of those may need the RAM to hit DDR2-900+ speeds.

You will not even need to hit full DDR2-800 Speeds.
Things to look for are relatively low timings and voltage.

Crucial Ballistix are the best quality of those 3. I would avoid Corsair entirely, as they tend to use low quality memory ICs and Kingston tends to be overpriced. However, your CPU will most likely max out before the ram with any DDR2-800.

I see, thanks guys. So I would be fine with some ADATA extremes? (4-4-4-12 with a voltage boost to 2.1-2.2v)

Also I know GSkill is another favorite for value ram...does either have a particularly better reputation over the other?

The ADATA Extreme should be fine, really, get whatever DDR2-800 is cheapest, as they should all fit your needs with such a high CPU multiplier.

great, thanks! actually decided to go with the GSkill, as many many many others have on newegg.