No chinese Algae Eaters.....unless you have an algae problem, they do clean the algea well, BUT they are not the friendliest fish in the tank and they can turn on the others, and they are hard to catch to get rid of them when the problem is gone.
Siamese are much better citizens in the tank and they do a nice job. I have 2 SAE's in my 55gal and they do a nice job and also pal around alot.
Plecos can get pretty large, I like Corys they don't bother the other fish and they stay fairly small (about 3") and mine is very active cleaning.
A combination is a good idea...ghost shrimp in the mix are a cheap source of bottom cleaners. But no matter how many of these you have you'll still need to vacuum the gravel.