Welcome to Amiga.org! I'd recommend an accelerator card and some fast memory to bring that A1200 up to speed. As for WHICH card to get, that's always the trick.
I've got a Blizzard 1230 in mine with a SCSI adapter hooked up to a malfunctioning SCSI hard drive, and better functioning SCSI CD-ROM drive. For the price the best way to hook a CD-ROM drive up to an A1200 is probably a buffered port splitter for the IDE interface. SCSI is so expensive nowadays.
One thing I forgot to mention is that the Power Supply that comes with an A1200 is weak. An AT power supply with adapter is much better.
If you need any further advice just drop back in to Amiga.org and we'll try to answer all of your questions!
