>I have an A1200 with Blizzard 1240 and the SCSI kit attachment.
I guess this means Fast Wide SCSI?
>1. WHat kinds of SCSI hardrives can I use?
All single ended (SE) or LVD/SE ones. No (old) HVD. Drives with SCA port need an adapter.
>2. Whats the biggest size?
AFAIK the largest SCSI drives are 300 GB. You can also use a SCSI-SCSI RAID controller to 'bundle' several drives to a single logical one.
>3.Where can I get them?

?
Local dealer, mail order, ...
Probably starts ~$350 US.
>4. Can I use SCSI III and UltraWide SCSI? and whaever other SCSI out there exists?
Yes, you can use Fast Wide, UltraWide, U160 and U320. Even SAS if you can find an adapter.
>5. Don't I need some kind of adaptor to fit it onto the Parrallel port looking connector of the Blizzard SCSI?
Dunno what it looks like, but a wide SCSI port/cable fits all drives from Fast Wide to U320.
>6. WHy the heck do they have so many different SCSI connectors?
The standard has grown over some decades and is very versatile.
>7. Anyone agree with me how stupid this is?
Yes.

>8. What of this ACard thing? I just heard about it?
It bridges/adapts ATA/IDE devices to be used with a SCSI host adapter.
>9. Isnt the ACard too damn expensive ($100) to justify using a IDE on a SCSI port?
Yes. If you don't need a TB drive, just get the SCSI variant.
>10. Even though SCSI harddrives are more expensive, still it would be cheaper than buying an ACard and an IDE of the same capacity???
SCSI drives are usually 'enterprise' class: faster, longer life, but possible more noisy than 'consumer' IDE drives, esp the higher RPM types with 10k or even 15k. Apart from that, a 1 TB IDE drive plus ACard is cheaper and available.