Hey, everyone...1st post so forgive the newbie please.

I am looking for an entry bike to get back into this sport. I haven't ridden much since high school (~10y ago) but a few of my friends at work ride (one competitively in college; he has 2 race-prepped C'dales which we rode last night ~15 miles) and I'd also like to use it for part of my fitness regiment and for a little reflection ("ME" time). My aforementioned friend used to work at a bike shop and they have a few that I'm looking at. They are:

'04 Raleigh M-50 - $265
'04 Raleigh M-60 - $385
'04 Trek 4500 - $340
'04 Trek 4900 - $450
'03 Cannondale F300 - $500
'04 Gary Fisher Hoo Koo E Koo - $550

I'd rather stay in the $3-400 range, but I'll go up and grab a more expensive bike listed if it provides a definitive advantage (I also may be able to get them for a little bit less than the prices above).

What do you all think? I haven't bought a bike in a decade and need a little help with what is good and what isn't (frame, fork, components, etc).

Thanks for any help in advance!
-Matt