That's a nice setup you have there, Golfman65. It's a setup that will provide you years of pleasurable casting and catching, with no need to upgrade as your skills improve.
Full sinking lines are not any harder to cast. I find that my Scientific Anglers Uniform Sink line is one of the easiest casting lines that I own. The skinny diameter and slightly heavier head makes the line shoot very easily. A full sinking line, like an intermediate or a faster Type II, is definitely more usefull in the lakes...but a sinking tip also fishes well off of shallow structure and the edges of weedbeds.
My lake rods all have two lines, and I can take any one rod and be able to cover just about everything. One spool has a Rio Versitip line, and the other has a full sinking line of some sort. The Rio Versitip may be expensive initially, but it really saves you money in the long run as it's like having four premium lines in one, and you cover lakes and rivers with it. You also don't need to carry or buy as many expensive spools. Just some food for thought if there's room in your budget.
Welcome to flyfishing...I know you're going to have a blast!