The perennial "which iPhone should I get" question (16 GB EDGE vs 3GS vs ???)

I know. I’m sick of them, too, but here I am.

So, some of you may have read that my iPhone EDGE was stolen. Turns out the insurance paid out $285, which I can apply towards the cost of a new phone. I’m sentimentally attached to the EDGE model (and pragmatically attached to the significantly lower monthly rate), and believe the bump up to 16 GB (from my original 8) would be a just improvement, so I’m considering buying a used 16GB EDGE model off eBay.

My main complaints about the EDGE phone are the abysmal volume of speaker/ringer and the nearly equally abysmal call quality. I’ve read that the 3G/S call quality isn’t any better although the speaker volume is improved. My main uses are internet, text, music, phone, occasionally the camera, and some apps, but I’m really not an app fiend. I don’t care about GPS. Video would be fun, but not necessary.

So will the EDGE have functional longevity to justify hanging on to the old tech, or am I trying to sign up for an obsolete phone?

If you’ve already walked down the path of upgrade, what’s your take? Is the upgrade worth it for someone like me?

I would consider other phones/carriers, but I really like the soft keyboard and the interface, unless there’s something else out there that does the job better. Doesn’t really seem like there’s anything to match. I’ve tried the DARE and wouldn’t like it.

EDIT:: stereo bluetooth would also be a nice to have, but not necessary.