If you are looking at line 6 stuff you should consider their actual tube models that have the effect modeling as well. They are excellent!
Regarding the song books, I have a huge collection of them and what I can tell you is that in order for them to be worth it, you need to LOVE the entire album or most of it. Otherwise you use it for one or two songs and it just sits there gathering dust.
Right now I’m in a huge dilema because I have a rack case for the amplifier head I currently use. In that case is a power conditioner, my amp, a compressor, and a wireless mic receiver.
The Ampeg PF500 is not rackmountable and I want to move away from having a pedal board as it is the part of my set up that causes me the most trouble. In a perfet world I would be able to rack mount the PF500 and get my own 4 or 5 space rack and throw in a rack tuner, compressor,wireless receiver (the line 6 G90 model, I have the G50 which is a pedal receiver) and maybe even a tube preamp.
Or I can just really go to town and fix my pedal board and make it indestructible.