I haven't been playing live for a while. The studio work has kept me busy enough. But, I used Sonar on a laptop playing all the midi in to plugins and running audio tracks of whatever rhythm guitars and background vox. The rhythm guitars were mixed to only come in when I trade off to leads. I also played keys the same way.
The lag time was nil between songs. Oh, and all my sequences were played by me and a few of my favorite local guys who worked in the studio with me. No internet freebies. I always liked to take songs and put my own stamp on them even when I was playing with a band. 
This setup had replaced an old Yamaha W5 and W7 workstation. I would play and arrange everything in the computer in Sonar and then save those songs to floppies (remember those?) I could program up to 16 songs or a set and save that set. I had many different floppies for different gigs. Jazz, pop country, rock. When I found I could use Sonar to fill in those audio tracks for me there was no turning back. Sonar filled the bill rather well for a long time.
I made a ton of money but it sure got lonesome up there sometimes.