The bundle has a few games I already own, but it also has several games I already had in my wish-list ... totalling way more than $20. So, just on the practical level, the bundle paid for itself.
Add to that that the money spent is actually a donation to Doctors without Borders, and to be used to help efforts with the Haitian disaster relief? It's a no brainer.
Do something good. Get a bunch of stuff I already wanted (and already planned to buy). Where's the downside?
I do want to thank RPGnow, DriveThruRPG, and OneBookShelf for putting this all together, and thank whichever people are giving up their income from these products, to go toward the Haitian relief effort. Those are the people who did the really great thing here. This was an excellent idea on how to motivate the gaming community to make something great happen. And, judging from the way it has overwhelmed the download servers, it sounds like it was an amazing success.