If you make your first threa HERE, someone will greet you with lots of info.
But I'll try and answer a couple for you.
1. The new Wii's that don't have Gamecube compatibility can still be softmodded, but people have been having trouble with the new wiimotes with the wii motion built in.
2. Any Wii can be softmoded. But the reasons in 1. I would go for one with gamecube ability.
3. Read the info after your intro post to answer any more questions.