Garmin has added support for custom raster imagery to the Colorado, Dakota and Oregon product lines. This will allow you to add aerial photos, USGS topo maps, etc. to your device. You’ll need the latest beta firmware for the units (betas have not been posted for all units yet), but the process is laid out in this post. Basically, you create an image overlay in Google Earth as a .kmz file and transfer it to your unit.
I’m heading out into the field later today and will try to load a U.S. Forest Service topo quad, if Garmin posts a beta for the Oregon 400t this morning.
Scott at GPS Fix has more details, including beta firmware links.
UPDATE: Here’s the Oregon 400t beta firmware link and a screenshot from the USFS topo map I did this morning:
The 
has a 4.7 inch touchscreen, voice commands, Bluetooth for hands-free cell phone use, lane guidance, 3D landmarks and AAA TourBook. In other words, it’s loaded.
Garmin has announced a new marine planning software desktop application dubbed HomePort. After the introduction of this and 
. This looks like a slightly stripped-down version of the GO 740 LIVE, minus Bluetooth and voice commands.
I learned the other day about a 
from the FCC 
is the first and only GPS designed exclusively for triathletes. It is waterproof (to 50 meters!) and can go for up to 20 hours on one charge. Targeted to multi-sport athletes, the 310XT can categorize the activities in your workout and log transition times.
If you’re a Garmin owner and aren’t aware of all the free maps available for your unit, you’re in for a treat. Detailed 1:24,000 scale topo maps are available for most states in the US, as well as for some foreign countries. We’re also beginning to see transparent trail maps that can layer on top of topos.