I like all of Toad's voices. The cool-type voice in MK64 and the croaky-type one in the more recent ones. I don't really remember the MKSC "Ya-hoh!" one, but I don't remember having a problem with it. Yoshi's old Zip-zoo noise was awesome, it somehow fits him and is unlike anything you've ever heard before. MK64 added ways to make it match his feelings... Happy: Za-zipzo-ZIPzoo! Falling off a cliff-Zip-zoop-zugh... But the new one's good too. "Hup! Hoooaaaghh....!" "Wah!" "A-woah-woah-woah..." I still don't know why he shouts "Yoshi!" but whatever...
Toad and Yoshi are both perfect characters. In the next Mario RPG, where toads have more prominent roles (as do yoshis,) I can picture a toad army where they have camouflage heads and sunglasses, and Bob-Ombs... that would be awesome. Although, they have to fail their job so Mario has something to do. It's been a while since Mario's ridden Yoshi, too... what was it, SMSu?