Another vote for the Blue Tongue Skink - they do get big though (I have a Northern that's over 2 feet long), so you need to account for the size of the enclosure - other than that, they're pretty simple, and the variety of food you can offer is kind of fun (everything from greens to snails to...
My ghetto 20 gallon long enclosure. I'll eventually do some fake rock stuff.
The hot side...
The cool side...
The resident...
I'll toss my pimped out beardie enclosure here too...