There are LOTS of different types of lakes, strategies, and gear sets. This is just a small sample of some of the setups I'll use on lakes. Boats, seasons, and water temperatures change everything but a well rounded assortment of strategies are essential for finding the depth, fly, and speed at which to present your flies.
Deep Sinking Line Rigs
You'll want to have a sinking line, preferably a full sink, to work the deep shoals and ledges if the fish are sitting off the ledges. You can work a leech or swimming nymph on this line, using a strip strip pause cadence can be deadly. I like a 9'6" 6-7 weight rod for slinging big casts with a full sinking line.
Slow Sinking Intermediate Rig
This is the most versatile, most common, and the #1 rig I would use if had to choose ONE setup. In the video I'm using a RIO Streamer Tip with a clear intermediate sinking tip. It drops at 1.5 inches/per second. I use this line in rivers as well, but a dedicated lake angler should probably use a full sinking intermediate line to get a level retrieve. Leeches, soft hackles, swimming nymphs, or even a Chironomid style fly can be inched along using this line. A sturdy fast action 9' 5 weight will do fine here, but many lake anglers prefer 9'6" - 10' rods.
Floating Line Rig
A floating line is essential! You can carry an extra spool, or another rod but you'll want the options of using small indicators with Chironomids, or dry fly fishing during the hatch. You can also do well using jighead style leech flies and working the shallower drop-offs.