I love my Magellan Triton 2000.
There are two great software packages that I use w/ it:
National Geographic TOPO! State Series (freaking love this software, it allows 3d-flyovers of trails, and has a ton of features), which allows one to create custom Topo maps and upload them to the GPS.
Additionally, it also supports TOPO! Explorer, which is more of an online application, but you can build hybrid topo/satellite quads and upload them to the Triton. It's a little more expensive than the state series, but having support for hybrid maps is nice.
I know others have topo/hybrid mapping features, but I wanted to point out the Triton series has full support for them too. (most dont actually seem to know this -- I am able to store 1/3rd the state of texas in detailed topo maps using a 2gig SD card on the triton.)
The fact that it's water-proof adds more value for me, as I also use it in my kayaking adventures. =)
Some people like their phones, but I've yet to find one that had nearly the GPS antenna and signal my hand-held unit does (my hand-held works down in valleys, under full tree and cloud cover. My phone can't even find a satellite half the time when it's overcast. Let's not even talk about the time I couldn't find Long Ranch b/c I was relying on the phone nav, which not only stopped updating when I left 3G service, it also blanked out the existing map. Fortunately, I had a back-up plan and my triton was in the console, with a waypoint for the park.)
!c