I would get a 100 pound leather heavybag. Everlast makes one like this and it was like 100 bucks. If you are willing to pay more than you might want to look into getting a mushroom shaped heavybag. They are good because they allow you to realistically practice uppercuts. As for gloves, get at least 12 ounce bag gloves. They will protect your hands better andd get your arms into better condition. Ringide, Title, and G&S make a real good bag glove. You can check all their stuff out online including bags
I think I'll go with this one--the 100lbs http://www.everlast.com/everlast-nevatear-training-bags.html
I actually do use the 16 ounce Ringside ultimate bag gloves.A great and durable bag glove. You are right in that the added weight really helps with the conditioning, and improves stamina and handspeed. But you do need to be in good shape to work with 16 oz bag gloves. For someone just starting out, I would suggest they start with 12 oz bag gloves, and once their conditioning improves, then "work their way up" to the 16 oz bag gloves.