In addition to the Harley tool kit, I also bought the Cruztools H3, a Slime Compressor, and a S&G Tire Repair Kit. I got to use some of these on friends bikes a couple of times on the way to Sturgis and back. Snap-On makes a more comprehensive kit than the Cruztools, but it's very pricy, and surprisingly for nearly $300, is missing a T27, which is a must have for Batwings. Imho, the Cruztools is very nice quality and is an excellent bang for the buck for less than $90. I just added a T27 driver and a few other things, and I think I can handle 90% of what could go wrong on the road. If you're talking about tools for the home workshop, the sky's the limit. There I'd start with a nice lift - I love my SAM 2.
Hope this helps.