Second this guy's statement, trying to find a nice 128k for myself, not an easy task if you don't want to pay an arm and a leg
I ended up getting a 512Ke, my first and most beloved collectors item to date. Interestingly, during Apples "30th Anniversary" promotion, it was voted the most popular first Mac among the entire Macintosh community. It was one place ahead of the regular 512k, and 4 places ahead of the MacBook Pro. Therefore, it is not rare, but the right age and use balance for me.
It has the exact same beautiful Jobs design as the 128K, but with 512K RAM, 800K Floppy Drive, and the 128K ROM. This means I can actually have some fun with it for games and networking. I've hooked up a MIDI interface, LocalTalk Network adapter to add it to my AppleTalk network, a 20MB Apple HD20 Hard Drive, as well as an External 800K Drive. My pride and joy!
I even host a server from it, accessible via the internet though FTP. Seriously. I can take a picture on my iPhone 5S running iOS 8, and send it over the internet to the 512Ke, and view it right on the 9" screen. Hilarious clash of old and new and great fun to set up.
Basically, I'd jump at the chance to get a 128K for a fair price too, but it's good for very little else aside from a shelf piece. (A top notch one at that of course). I think the 512K, 512Ke, and Plus are better buys if you want to actually have a little fun with the system, while keeping the beautiful minimalist aesthetic of the 128K.
My biggest gripe about the Plus is the needless "MACINTOSH PLUS" written across the front. A travesty of art if there ever was one. Pointless and ruins the design boldly. Personally, if I ever got a (very useful) Plus, I would probably locate a 128K/512K with the Plus upgrade, that keeps the original front bucket. The plus is nice however, with up to 4MB RAM and SCSI, you can run almost any 68K application and even the versatile System 7. Loads of potential for fun projects there.
The SE, SE/30 are much more powerful and useful again, but far uglier collectors items in my personal opinion, despite being better made machines in a number of areas. e.g. Fan, Very Expandable RAM, SCSI, Expansion Bay, etc.)
Happy hunting!
