Ive found I much prefer to make THINGS (Like models/prefabs) than actual maps. It is just more my thing. Im currently making a VERY well made and realistic A10 Tankbuster. This can be used as a Prefab, or just to look at.
Here is what the real thing looks like.
http://www.afterburnerseminars.com/resource/downloads/hi_res/A10.jpgIm having alot of fun, soon it will be finished - with all custom textures and whatnot. Im very proud of my current model of it I'm making (Actually made in Hammer), it is nearly IDENTICAL to the real thing.
Next up will proberly be a tank or maybe a chopper.