Glad to see someone new excited about this phone.
The Evo's really nice, as is Sense, but the Epic has a few features I haven't found anywhere else -- and I lo-o-ve its screen and keyboard, and five ways of inputting text. I've written entire stories on this thing using TextEdit.
You're in a great position buying now, as the worst bugs and issues have been addressed by early-adopting fools like me. You'll have 30 days to see what this phone can and can't do without waiting for updates beyond Froyo. I've had mine since launch and love it.
Since you're mentioning Launcher Pro, I assume the look of the desktop's important to you. I'd suggest reading the
what does your screen look like? thread for lots of appearance tweaks.
Lists of the best apps are also a search away in these Epic forums. See thread titles under apps for longer lists than you'll probably get here in a recent thread (since we're only over a month from launch).
For increased battery life, I know of nothing better than
Juice Defender. That and turning Airplane Mode on and off when you restart your phone should keep you reasonably charged. We're all awaiting an extended battery by Seido, the same company that makes the Evo's.
If you have a Mac, you'll need to click the Debug option on your Epic to have it recognize the SD and export your contacts and calendar to Google. I have a Macbook Pro for music work and a PC for everything else. My transition was swift and unproblematic. You can also transfer files using Bluetooth.
The mere fact you're starting out wanting to tweak your desktop makes me think the Epic will be a great fit. People who are weaning an iPhone addiction and don't care about keyboards should probably get an Evo: Comparatively seamless operation with less geek candy.