i have a crate v33-212 combo amp and i want to replace the speakers. whats the rule on speaker wattage? i see speakers that are rated for 15,30 50 watts etc.i am not sure of what speaker to buy. thanks.
If the speakers' wattage rating is equal to or greater than the output of the amp then you will be good.

Since its a low wattage amp then you will be able to put just about any speakers in that you want.

What styles of music do you play?? If we know that then we can make some suggestions as to which speakers you should check out.