Switftech is great if you want to pay an arm and a leg, and still have to buy a separate fan. Sure they produce by a long shot the best results, but I'd say they are a little too expensive.
The wattage of the 2100+ is still somewhat less than the old t-bird 1.4Ghz, so the Volcano 7+ will do you just fine, but I understand the clip isn't all that it could be, it's more or less the same as the clip on my Volcano Cu6+, which isn't terrible, but only clips onto one lug on either side of the socket, and requires the use of a screwdriver to install.
If your into overclocking, there are a multitude of choices that are cheaper than Swiftech.
Don't get me wrong, I know that Swiftech coolers are incredible, they cool better than nearly every other cooler out there, but they are very very expensive.
frostytech.com is probably the best site I've read on this, they have comparisions on hundreds of coolers.