I like classic rock the most.
Bluegrass is excellent. I am (still) a big fan of Hot Tuna. Jorma Kaukonen is amazing. Actually, growing up Hot Tuna was my favorite band.
I love seeing Jorma in concert as I can easily walk up to the 1st row (not a huge audience) and not only hear Jorma playing but see him play his guitar. Watching Jorma play a guitar is better than any math lecture I ever attended--and I love math.
In two weeks I will be going to see Bobby Weir four times(!!). What can I say, I am still a true deadhead.