Well, I got a super-cheap discontinued 64meg display model a couple years back, so I can't really help you with personal experience.

I can, however, suggest a couple of good websites.
Try going
here. That's the
epinions listing for MP3 players with at least 1 gig of storage capacity. From that page, you can further narrow it down by choosing a weight range (unfortunately, that's in ounces), a price range, or a manufacturer. Epinions offers product information along with reviews from fellow consumers.
You can also try
cnet 's professional reviews of
mp3 players for more information.
As for battery power, some MP3 players use standard size batteries (AA or AAA), so you have the option of finding cheap spares. You can get rechargable batteries, regular batteries, or both. If you're looking for long usage time, that's probably your best option. Get the rechargables for regular use, but take some extra non-rechargables along for those long trips.
Hope this helps.
Paul