It's worth having if only because it should be quieter. There are better options in that category, namely the ECO C240, which has up to four fans and two 120mm radiators, but the corsair had its problems fixed in later revisions from what I'd read a few months back. Either that, or a good air cooling setup. I'd suggest the Noctua DH-14 if you're going all out or the Zalman 9900 if you want to take that one step back.http://shopping.coolitsystems.com/s.nl/it.A/id.2234/.f
^^^ ECO C240http://www.newegg.com/Product/Product.aspx?Item=N82E16835608018
As to thermal grease, I'd use AS5 which spreads well and is easy to apply. (The most overlooked factor in a selection IMHO)
Or, I'd get some of Noctua's thermal grease which I've heard is really good.