I have 3 gigs of Geil in my rig right now (2x1gb, 2x512). It's not the cheapest Geil, but it's close, so it doesn't OC very well. I've never had a problem with it, I've bought from Geil thrice and would do so again.
HOWEVER, I bought myself two 1gb sticks as shown in the link for around $170 shipped. I suppose this deal is alright, but it's definetly not the lowest price. Keep an eye on the single sticks as dual channel sets are just a marketing ploy to charge more money from users.