Do I need a bootloader (GRUB) to dual-boot from two separate HDDs ?

[Amamba]

Since I started getting SMART "dire warnings" I just replaced my main HDD with a new drive, and migrated W7 to it.

The old drive (still installed) has the original W7 install. I can chose which one to boot from if I hit F12 at reboot.

So, can I install Ubuntu on it, without installing GRUB ? I.e. using BIOS to chose which drive to boot from ?

About 2 years ago I used to dual boot OpenSUSE and XP, however the last Suse automatic upgrade got royally screwed up so once I got the new machine I never installed Linux on it. Now seems to be a perfect opportunity.

Also, - a different question - why is 32 bit version "recommended" ? What's not so good about 64 bit ?

Thanks !

[Quackers]

If you don't install a bootloader it won't boot!
To be honest, if you're getting smart errors it may well be a waste of effort installing anything on that drive.