Personally, I don't worry about it too much.
Right now, I've got a collection of 3 different media types (Memory Stick, Secure Digital and CompactFlash). LOL
Heck, I got a heck of a bargain recently at a yard sale.
Someone hada fewCompactFlash cards sitting on a bookshelf. I asked how much. They said 5 dollars for all 3 cards (including a 256mb and 128mb Lexar CompactFlash Card -- although the 256mb was only a 4x card).
Did I need them? Nah... The only camera I'd even want to use these old slow cards in now would be a Nikon Coolpix 950 I use from time to time for macro shots.
I can remember paying a lot of money for cards of this size a few years back. Now, you can buy 1GB cardsfor under $100.00 brand new.
Again, I wouldn't sweat the media type too much if buying a new camera (even though I've already got some cards). From my perspective, by the time you get ready to upgrade, you'll probably want newer, larger, faster mediaanyway (and media prices should continue to drop).