Other than chocolate or plain? I'm seeing all these wonderful recipes here and now I'm totally overwhelmed at figuring out which to use for that anniversary cake (w/peanut butter filling).
I wish I had time to try them all to get the feel of how each recipe holds up. Can you make any recommendations? I'd like delicious (of course lol!), to work w/the peanut butter, and something that would work with the tier.... maybe the tier doesn't matter since it's supported (I still have tons to learn!)

I was thinking of trying Toba Garrett's moist yellow cake.... but then maybe that wouldn't be the best... I don't know. I want to be experienced enough to just know that "oh, this xyz recipe would be perfect for that". So until then, I'll beg for input from you experts!

I'd been having this same problem, so I started experimenting with some of the recipes in these "Post your best cake recipes" threads:
http://cakecentral.com/cake-decorating-ftopict-365233.html
http://cakecentral.com/cake-decorating-ftopict-579499-.html
Believe it or not, the ones I've liked the most so far are the original and chocolate WASC recipes. This came as a big surprise, because I'm basically a scratch baker and don't like cake mixes very much, at least not by themselves. Either one of these would go great with a peanut butter filling (for which there is an incredible recipe in the recipe section here, by the way). I'm a big fan of chocolate with peanut butter, but that original WASC recipe would be very tasty with that filling, too. I made the apple cake in that first thread the other day (grated the apples instead of chopping them, and used a little more cinnamon, but it was very good and very moist) and I think it would go very nicely with a peanut butter filling, too. Best of luck, whatever you decide.