I've kind of got my heart set on an Electra Townie. Internal comes in either a 3spd or 8spd for Townies -- and the 8 speed is a little pricey. I would like to keep this bike under $500 since I need to buy other things as well (bike rack, car rack, fenders, etc.). The Townie comes in a 7spd, 21spd or 24spd derailleur setup but I think anything significantly over 7 is overkill for my needs.

I'm just wondering how limiting 3spds really is, and how much maintenance should I expect if I go for a derailleur?