I play on Live and I enjoy myself most of the time. I've only seen hackers on Unreal T. and Wolfenstein. M$ is supposed to be working on patching those games to fix the problem as we speak though. I'm not sure if its bad code on MS's part or the developers but it's somewhere
As for knowing the spawn points, well that comes with playing the game. I've never met a spawn camper that couldn't be wiped out. It might take a bit of work but it's do able. Also, if the other team can get someone in place to set up a spawn point sniper that's some bad teamwork going on there somewhere.
As for lag, well it's the internet. People are supposed to be using a cable connection or better but some people don't. Most games have a connection speed or status bar next to them. Are you using that before you pick a game? Try sticking to games with a dedicated server for a while and see how that goes.
Lastly, for the "assholes" online. Well again, it's the online gaming community. The only thing I can say about this is either get the host to boot the guy or leave the game yourself. Just try to take everything in stride. I've met my fair share of pain in the asses online too.