(idiot) ^
Think small, halflife uses an engine over 5 years old and most of your 'grand ideas' will have to wait till halflife 2 or be moved to something more scalable.
Whats new is generally good. Learn to texture for yourself, a new coat of paint can give life to a dull map. A FRESH (custom textures) coat of paint can put your map above those that use whats included with the mod you're mapping for or the standard halflife.