So I just bought Black 1 for the DS after not having played since Gold/Silver...how screwed am I going to be?!
Starting it tonight...should I be playing ruby/sapphire first? Am I going to regret going with Black first?
Since you are a returning Pokemon player, I would have recommended buying Black 2 over Black because Black and White 1 contain none of the original Pokemon until after you beat the game. That lack of familiarity coupled with a bunch of new mechanics may be a little overwhelming at first, but if you can get past these potential issues, you'll have a really good experience.
As for Ruby and Sapphire, I don't think you'll regret a thing about not purchasing it first. Ruby and Sapphire is akin to Windwaker in the series, it ventures away from the original games quite a bit, and depending on who you are, it is either your favourite or most hated Pokemon version (I'm in the latter).