Huge fan of LaBrie; when I bought Images and Words back in '92, it was Portnoy's drumming and LaBrie's singing that hooked me, and to this day, that is a top ten all time album for me.
As for Jagger, huge Stones fan - I have almost the complete catalogue which is saying something - and you have to see him live to get it. I know it's easy to mock him for a lot of things - his solo albums are forgettable, as are most Stones videos - but I saw them on the Bigger Bang tour, two and a half hours in a stadium, and yet, when the entire place was bathed in red, and he was out on the catwalk singing "Sympathy For The Devil" it was captivating. Almost dangerous (I can only IMAGINE what that was like seeing that in '71 or '72...), or at least as dangerous as you could feel watching a 60+ year old man in a football stadium in Connecticut. He also has - and this isn't to be underestimated - an amazing knack of channeling the music he's playing. He can sing blues - Delta blues, British blues, Chicago blues - rock, dance, disco, punk, country... few singers have that level of breadth without sounding out of place or like a cheap caricature (which he also has on rare occasions).