Ahhh... you have much to hear.
All Symphony X albums have great guitar solos, but I think the albums with the best riffs are probably the Odyssey and Divine Wings of Tragedy.
As far as single songs go, I guess I'd recommend you check out Sea of Lies, Smoke and Mirrors, In the Dragon's Den, Evolution, The Turning, Inferno, The Damnation Game, A Fool's Paradise, and Out of the Ashes for some short, guitar driven tracks.
Check out songs such as The Divine Wings of Tragedy, Church of the Machine, Awakenings, The Edge of Forever, Rediscovery Pt2, and the Odyssey for a better idea of what Symphony X is all about. These are some of my favorite songs as well.
And if you're going to buy an album, I'd recommend you start with The Odyssey or Divine Wings of Tragedy by your tastes, but V, Twighlight in Olympus, and Damnation Game are great albums as well. The first album has bad vocals, so there.