A few more thingsSo I got the 512MB kit offa woot.com for $85 shipped..then it appeared in Bay Area Fry's ad for $100 with the 1gb player (good til Aug 22 2006! and only $130 after that)...so I got that and I'm gonna give the 512 to my girlfriend.
I put a 2GB Kingston SD card that was on sale for $25 after rebate...so I have a 3 gig player for $125 with a sweet sound dock. awesome. I considered ordering a 4gb card but wanted to buy it from a store so I could return it if it didnt work but I don't have to. Also, navigating through 4gb file by file would be tedious, since the CE-IV doesn't have menu-style song selection...just a big list of all your mp3s file by file. And, you have to switch between internal and external memory manually; it doesn't treat the two as one big drive. Some drawbacks, but still a great usable player at a great price with the sound dock. It could also be advantageous if you want to have two separate groups of music (i.e. using the internal memory for working out and the external music for the rest of the stuff you wanna listen to...etc.)
Also, the dock powers the MP3 player so you don't need even need batteries when you're docked. Unfortunately, it doesn't charge a rechargable battery if there's one in the player (although the manual says you can buy an adapter to connect an AC adapter to the CE-IV to charge a battery while it's in the player...I'm just gonna take it out and pop it in a charger.
You might have read reviews online that complain about a flimsy battery cover. It's not that bad. Seriously. You'd have to be pretty rough with it to break it.
The removable docking thing also fits really well underneath a car stereo in most cars, then just plug an aux input 3.5mm phone plug into the back of the dock for clean mobile tunes while the mp3 player sits right up in front of your head unit so you can skip tracks and stuff.
Final take: get this if you want a cheap relatively low capacity (512MB-3GB) player and like listening to a bunch of songs rather than picking out individual songs (which is inconvenient due to the lack of genre->artist->album->song type menu system). Shoot, even if you just have an iPod, buy it for the dock and give the player