I play anywhere from 3 to 8 hours a day. I play atleast an hour every day.
To make this time useful , I suggest practicing scales using a metronome. Increase the speed as you go , and only increase it once you are 100% comfortable with the scale at that level. ( I usually make myself play it atleast 10 times flawlessly before moving up. )
The type of mysic I play varies greatly. From Eric Clapton , to Creed... From Metallica to Slayer.
I'm like you though , I love long solos , and fast heavy rhythm's.