Dazed and confused.
Join Date: Jul 2008
Location: Dublin, Ireland
If you intend on using that list as a starting point, I'd go with it for now before buying anything else. What a lot of people do jumping into the hobby is buy loads of stuff, and then get overwhelmed by the sea of grey plastic in front of them. Build and paint it squad by squad, setting yourself realistic goals. If you decide to add the extra stuff later, that's easy to do, but for now I'd concentrate on getting a small, viable force on the table.
Another thing I'd mention is that you should take the minis themselves into account when list building. If you want to get an army painted, the easiest way to stay motivated is by painting minis you like. A horde army like IG can be monotonous to work on, so don't be afraid to throw in a unit of ogryns or ratling snipers to mix it up a bit.