If there is an REI close to you I would check in there for an entry level Novara or Scott. They are very user friendly and have free classes on maintenance. They should also know about local riding groups.
$400 will also pick up a good Craigslist bike if you have someone who can help you look over a used bike.
Good luck and keep us posted on what you end up with.
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I think its disgusting and terrible how people treat Lance Armstrong, especially after winning 7 Tour de France Titles while on drugs!
I can't even find my bike when I'm on drugs. -Willie N.