AmigaKit already posted, but I was going to recommend you check their site out. They have new and refurbished Amiga 1200s in the original cases, and I guess also in tower cases. Personally I'm not sure how I feel about towerized 1200s... but lots of people like them, and theyre easier to expand. Most Amiga tower cases cost a ton of money though (over $200 for an empty case!!!). For the cost of a 1200 and an empty tower you could get a 1200 and a kick ass accelerator. If you can get a towerized 1200 as a package deal though, that might be a good choice. You might want to look at some of the bus boards for towerized 1200s, some of which have Zorro II, III and PCI slots, and some weird Zorro IV which was a post-Commodore invention.
What do you want to do with the Amiga? Thats a big factor in what you need. For someone like me who uses Linux for most things and the Amiga and Commodore 64 for retro geekery (games and demos mostly, I want to learn music making too though) the needs will be much simpler than the needs for someone who wants to use an Amiga as their main computer.
For retro gaming/demos: An Amiga 1200 or 2000 with a 68030 accelerator and some RAM expansion, and a way to transfer files from PC (either a PCMCIA ethernet card on a 1200 or a CDROM on a 2000) as well as a decent size hard drive (if using an Amiga 2000, you'll need a SCSI or IDE card to add a hard drive - SCSI cards are common and cheap). A 1200 has the AGA chipset that lets you play newer more graphically intense games and demos, but most classic games only need OCS or ECS which a 2000 can play just fine. Some real old games and demos dont easily play on 1200s. 2000s are more expandable since they have zorro slots. Accelerators are more common for 1200s, but it seems that 2000 accelerators are cheaper (if you can find them).
If you want to use an Amiga as an every day computer, you'll probably want a 1200 or 4000 with a 68060+PPC accelerator, lots of RAM, a scan doubler/flicker fixer or graphics card, an ethernet interface, and probably a bunch more stuff. Personally, I dont understand why people go this route, but whatever floats your boat.
