Morse has certainly been my biggest influence (2nd: McLaughlin). His video "The Definitive Steve Morse" from Warner Bros. Classics is a given, as is the book "Best of Steve Morse and Dixie Dregs" from Cherry Lane. Both are compilations of other, more varied material - there's a (OOP) book out for each of the great SMB albums of the golden era - High Tension Wires, Southern Steel, Coast to Coast, Structural Damage - if you really want to go deep into searching for out-of-print material. Another essential is the SMB "Live at Baden-Baden" video - it's right from the exact period as his instruction video, 8 of the songs in the "Best of" book are played, it really shows how he plays a song like "Ice Cakes" that took five Dregs to play - with a three-piece band! (now you try it...
Classical left-hand technique is essential, as he often plays with two or three voices moving around - he has a degree in classical composition after all, and classical guitar was his "major" instrument. Another huge influence on his soloing was Bach's "Partitas and Sonatas for Solo Violin", he's specifically explained how that was the tool that broke him out of copying Cream & Hendrix pentatonic tunes. You'll really, really need to learn to read.... his biggest personal influence was John McLaughlin, I hear it more in the variety and overall concept than in specific licks. There's some great information in the interviews on his website:
Steve Morse: The Official Website | Guitar Player for Deep Purple, The Dixie Dregs, and The Steve Morse Band
I was personally disappointed when he joined Deep Purple, he's way more talented than that band can contain - his "Sects, Dregs & Rock and Roll" DVD is of a 2001 reunion Dregs show, and it's sloppy and unfocused, what you'd expect from people who don't really play together anymore. However, he does make some money with Purple touring Europe, and money had always been a problem. After winning Guitar Player magazine's "Best Overall Guitarist" award, FIVE times in a row, Morse still
had to quit playing for a few years and fly commercial jet airliners to pay off the mortgage on his farm in Georgia (not
what your average guitarist does for a day job - gee I wonder if being a genius helps too?) Hell, Danny Gatton KILLED himself, I guess joining Deep Purple isn't the worst thing.
The luck of timing
of Satriani's and Vai's careers worked out better for them as far as supporting themselves, imagine being Steve Morse and hitting your creative peak at the exact same time
that grunge wiped guitar soloing off the map for a decade....