Ive been playin a lot of different things lately, but I want something that will really improve my playing ability and technique. Ive been playin for about a year and a half and Id say Im about average.

I was thinking maybe Glasgow Kiss, but I dont know if that would be too too hard. I can play super colossal pretty well, so i just dont know what I want to play. I want it to be an instrumental- guitar-heavy song. No singing so think Vai, Satch, them guys.
For the Love of God-Vai.
that'll keep ya busy for a while.
ESP Vintage Plus
Schecter C-1 Hellraiser
Line 6 Flextone IIIXL
Little Wing or Cliffs of Dover are both challenging in different ways, but amazingly fun to play.
Canon Rock is a fun one to learn, Cliffs of Dover is definetly a challenge, also look up Speed Metal Symphony from Cacophony

Stinger Smx
Hondo H-1
Fender Classical
Custom Mini Les Paul
60 watt Mega Tube
GNX4 workstation
6 pack of Shiner Bock
Glasgow Kiss would probably be a good choice. A little of everything - legato, alternate picking, sweep picking, string skipping - so it would exercise you in a bunch of ways. Take it nice and slow at first and build up the pace.
Ibanez RGA121 | ESP LTD H-1000
Axe-FX Standard