Thanks for the inputs so far. Keep them coming. From what I've read looking at the Gaia site, I think Topo Maps is related to Gaia. I'll give Gaia a shot.

Alukban, explain what Tomtrails does again? Does it just give the coordinates on demand in plain lat/long or UTM or what? How do you set up your phone for best battery life while using Tomtrails? How long does it take to get a fix when you turn the phone back on? Thanks in advance for any details.

It's hard to improve on the dedicated Garmin handheld GPS models but I already have the iPhone and will be carrying it anyway. And I would prefer something where downloading maps isn't such a pain in the butt and/or expensive.