Originally Posted by FunkyStickman

The only decent 7-speed bikes had cassettes, not freewheels... and 7-speed cassettes are extremely rare nowdays. Having owned both (my current bike is 7sp cassette) I can say that freewheels bikes are not up to serious miles, I've bent several axles and broken numerous freewheels, and I'm not a big guy.

7-speed cassettes, however, work great if you can find them.

For the actual speeds, if you have a triple in front, then 7 in back is fine. If you only have 1 or 2 rings in front, then 9-10 in back makes more sense. I'm fine with 3x7.