I live in Tahoe and three years ago I bought a Hobie 18. It is a great boat. Deffenitly glad I bought the 18 over a 16. It is a lot racier boat than the 16 plus if you are going out on Tahoe a lot you will want the extra length and better hulls. My friend has 16 and it doesn't do as well in the big short period swells. The TheMightyHobie18 will be hard to learn on single handing, but after you get some experience it is good to single hand up to about 15 mph. I single hand all the time on Donner.
Either way, buy a cat you will have a great time.