It really depends what you want to do with Windows, if you want to play games then your going to have to use Boot Camp, there are no other options, Q or Parallels will not do graphics acceleration or decent enough video performance (currently)
If however you only need it for apps, Word, Excel etc then Parallels will do you fine, maybe Q too depending on its performance (ive not tried it)
Incidentally, Parallels really is worth the preorder price of $39.. the latest beta is superb and its only going to get better/more features.
I have used Boot Camp with no problems at all not even a hiccup, it removed fine too when i was done with it, you dont get a boot screen with it, you choose what OS you want to boot into using Sys Prefs. (you can hold down a button and choose an OS at startup but thats optional & transparent otherwise)