We started with an albino checkered from a local aquatic/reptile shop, then we're given some normal checkereds by Pinjohn (he just wanted to share his passion for garters and get a new generation hooked, he did a good job).
Checkereds are good, but if you can find one I'd suggest a radix. One of our best, friendly, outgoing snakes is a parietalis. You can't go far wrong with any garter though.

Northwestern Garters are definitely not available in the UK, or at least if there are any over here whoever has them doesn't shout about it.