Could any of ya'll tell me what the best type of cake is for stacking?

Just about any type of cake can be stacked since the cake tiers don't have to support anything other than the weight of their decorations.

It's the job of your cake support system to support the cake tiers.

A lot of members like the SPS cake support system:

http://cakecentral.com/cake-decorating-ftopict-603925-sps.html

But there are also other methods:
(Illustrated with complete directions.)

http://www.countrykitchensa.com/wedding/assmeblingtypes.aspx

HTH