About the Atari 2600, check this out: www.qotile.net
There's a new soft coming up - the loopcart - but I'm using the synthcart (mainly sampled). There are some demos in the above site.
The lsdj version I'm using right now is the latest - 3.3.8 - but I still haven't tried it with the MC2.
The Spring King is a cheap spring reverb (mine cost me 90 Euros with delivery). If you're looking for that dubby feel on your snares/clicks/etc., you can't go wrong with it. It's daunting!