Now if there was a MP-E for Oly am sure the extra DoF available from being able to shoot at lower magnifications would come in handy! I stuck with APS-C for that reason. I don't do much telephoto work but I hear smaller sensors can be handy there too.

For most other types of photography I'd rather have full frame personally. Then again I always wanted something bigger than 35mm for landscapes anyway....just feels a bit unnatural to try and capture huge, spectacular views on piddly little cameras even although I've never even used MF let alone LF