Why do this I'm curious? I've got those on my commuter and I like them well enough. Is it a functional reason or vanity?

OP: It's been said and said well. There are a lot of seemingly pretty complete kits that will get you up to an intermediate level of work. I'd question the durability of the cheap deals you could find on eBay, but I'd still buy one if I didn't think I'd be using them too much. Problem is that most of the tools won't be needed on your older-style bike. Also, if you know specifically what you want to do, it may do you well to just buy the tools as you go.
I suggest you make a list of what you want to do, check out this guy (he is weird and not quite polished, but thorough and entertaining, plus he'll tell you every tool as he uses it and will show you ways around tools if they're not necessary) and then buy the tools for what you want to do.

Best of luck.