The best and cleanest setup would probably be:
1) A1200 - Small nice machine with AGA
2) Blizzard1230 - Best card there is with 030 also being most compatible, other 030 cards will also do though but make sure you stear clear of any Apollo card due to compability issues, GVP cards that requier special SIMMs that are impossible to dig up or any none PCMCIA friendly card.
Stick a 32Mb simm on it, any bigger simmsize usually means they might be hard to get to fit under the trapdoor.
3) FastATA - Speed up the IDE controller.
Stick to a 4Gb or less HDD.
4) Don't forget a bigger PSU (50W PSU form an old A500 should do).
Optional:
1) PCMCIA NIC - Allows access to internet and networks
2) Mouse/joy switch - Saves the mouseport from excessive wear and tear and also makes it easier to play 2 player games.
3) Paralell to 2 extra joystick ports addapter - Not used in many games but are usualy cheap so worth getting just to have just in case.
4) Scandoubler (internal preferred) - To be able to use regular monitors
5) BlizzardSCSI - Allow for an external SCSI CDRom wich is handy, squirrel interface is also an option though not as "clean" and not as fast.
For gaming there's not much else worth upgrading, at least not what I can think of right now.
