I agree Waterloo is a fine game to get and you'll enjoy the variety it offers, get the expansion packs too. The campaign map is very large and allows for some good maneuvers and situations. Well worth the time & a good way to get into the series.
Do consider the NWC, they have all the staff, members, opponents and support you'll need to truly enjoy PBEM Napoleonic gaming, besides the Blitz too. Don't mind the dust, as there was some loss of pages that occurred recently and the forums are currently having their settings worked on, but once you get a log in, you can see it all. Plus in the next few weeks a number of the websites will be replaced with new ones and in a few months all webistes will have been changed out.
Like mentioned above, a lot of folks are members here too, so you can carry your games to both places. The Blitz here is a good operation too, so don't ignore it.