Amazon.com has Region 1 DVD box sets -- S1 is already out, S2 will be out in early Sept., S3 is rumored for release in Jan. 2003. Presumably S4 will show up around early summer and S5 in early fall if they follow their usual about every 6 months release schedule. Depends on demand, I suppose, so we'd all better be demanding
Amazon.ca has just started up and is allowing pre-orders for R1 box sets in Canada, probably only S1 & S2 at present, but should be following the US parent company fairly soon in most aspects.
Region 2 (UK) has DVDs through I think S5, but as singles. If you have a region-free DVD player and want box sets, then Amazon.com is nicely priced and mostly available, but doesn't have all the seasons yet. If you want more seasons now, then Amazon.uk may be the better bet.
Since I don't purchase video tapes anymore if DVD is (or will be) available I don't know about what tapes are being marketed.
Oh, as far as I can tell, none of us bite -- although we can be very opinionated. Welcome to the board. Have fun. I certainly am.
BTW, Rowan is very wise. Listen to her. She knows lots of stuff. (Rowan, you can send my check to my usual address :evil