Samsung Wave
http://wave.samsungmobile.com/

N8 is pretty nice, but while it's cheap to start with it will take some time before it's in that price range.

Samsung Galaxy is not bad at all.

Touch screen devices are not for eveyone and somewhat time consuming to get used to. I recommend the Nokia N95. Unfortunately it works with ATT 3G and have to settle for 2.5G on TMobile. I ve owned this phone for 3+ yrs and find it extremely versatil and full or features. They go for around $150-$200. The best thing I like about it is that it always works, always. No bugs, no freezing, hang up or flaws. Menus open extremely fast, speaker sound is estremely loaud and clear for phone op as well as media. Using Skyfire you can open all and any web page and still get the flash files. I own the N900 but for everyday use I still use my N95. Dont get the N95 8Gb due to limited memory. The N95 has Sd slot and with 16gig ro 32 gig it ll be more than enough. It also has Word, Power point and Excel viewer and Adobe built-in. Software selection is also good for this device. I use my N95 with joiku as WiFi modem and get decent speed on my Laptop. Good Luck

Just ordered Nokia E72 as a second phone.

x10 mini or x10 mini pro. Hopefully released in a few weeks.

Sorry but I think the OP was looking for an phone alternative to the N900 within a $200 budget. It requires internal GPS and a 3G antenna.
Although the N95 meets the requirements, I don't think it is the worthy alternative. Because it is a (dumb)phone with many features rather than just smartphone.
I have one atm, and I can tell you after using a smartphone you notice how slow it is, Apps take forever to open. The GPS is very weak/slow even at hot spots. The screen is much smaller (bad for video/app contents) and has no touch-input. It has a slow and featureless web browser that lacks flash, so the 3G factor degrades. As a standard phone its great, just the many features it has, it cannot complete them properly.
I recommend firstly the Motorola Droid, then the SE Xperia X2, then the Touch Pro 2, then the Touch Pro, then the Xperia X1.
If you buy any of these, as an N900 alternative you would be quite pleased.
There are other alternatives as good or better than these, but they arrive in another form (candy bar, Blackberry) factors.
In my books key(thumb)boards, and its addition to the smartphone experience, are not to be underestimated. Especially ones that don't take screen real estate, are large and tuck away underneath the screen (ie slide) like the N900, unlike Blackberry's.

Thank you all for the suggestions. For those keeping track:

- Samsung I5700 Galaxy is not 3G on T-mobile
- Samsung Wave is not available in the US, it seems, and is pretty expensive
- Nokia 5230 Nuron doesn't have WiFI

At this point I'm probably going for an HTC Magic or a G1.

You can't go wrong with the G1 (HTC Dream).
Get the new Cyanogen MOD = Android 2.1 Eclaire final OS.

The only thing the G1 does poorly is memory.
Not enough RAM and ROM makes the gaming/video/performance experience bad ... but at least the user interface is still snappy.

Expect full speed with sound for GBA, SNES, Sega Genesis, Commodore64 and Atari emulation.
Don't expect PSX, N64, Dreamcast ... etc