Thanks for the replies.
So, what all do I need to get started?
I have lenses with 77mm and 82mm filter sizes. The big stopper being a given, what else would you recommend to start with? Glass versus resin?
1. I'd say resin because IMO the difference in IQ is negligible, the peace of mind not worrying about breaking the filter (as you WILL experience with the Big Stopper) is priceless.
2. The 82 mm wide angle adapter and either a step up 77-82mm ring or the 77mm adapter.
3. The filter holder (aka the Foundation kit)
4. You can use grad ND filters just by holding them with your hand in front of the lens (not possible with the Big Stopper for obvious reasons). Another option is getting them from the Filter Dude via ebay. I use these are they are as good as Lee.
5. 0.3 soft grad and 0.2 hard grad, the latter isn't strictly as necessary. I strongly recommend a reverse grad filter if you plan to shoot sunsets.
Mind you, HDR and PP can replicate grad filters in many cases, as Neuro said, and better in some. And a B+W 10 stop filter is arguably as good as the big stopper from various reviews I've heard. So that, and a step up ring might be reason enough for you to forget the whole Lee filter thing. It IS cumbersome.
Good luck with whatever you do, and please share the results (pics).
P.S. Edited to reflect the correction by Lintoni