I don't understand why you want to do "light workouts" if you're trying to bulk up. Doesn't make a bit of sense to me. Gaining lean mass is NOT easy, despite what you may have read. You'll have to bust your ass in the gym as well as the kitchen. 10-20 kg of LBathmate is a significant gain, especially for a few months' time. Light workouts won't cut it. I'd recommend something like Chad Waterbury's "Big Boy Basics," here:
http://www.t-nation.com/readTopic.do?id=459533
For protein powder, whey is good to have, but it isn't the be-all and end-all that some companies make it out to be. You need slow protein as well, such as casein. Biotest makes a good whey/casein blend MRP, but it can get a bit pricey (although if money is no object, go for it). I use a custom blend from
www.proteinfactory.com (click "The Lab") of 40% micellar casein, 30% milk protein isolate, and 30% whey isolate. It's like $40 or so for 5 pounds, and tastes pretty darn good. Post-workout it's optimal to have hydrolyzed whey, high GI carbs, and BCAAs. Surge is exactly that, and tastes really good (hydrolyzed whey tastes terrible, I tried making a custom blend using this and I can't even drink it). It's kind of pricey, but worth it IMO, probably especially when bulking.