That's fine, that works. If you want more of a 'terrain' kinda look, rather tahn flatness, check out these links:

http://qeradiant.com/manual/Terrain_Manual/start.html

http://tarot.telefragged.com/gensurf/

I used Gensurf in one of my maps, it's pretty cool (though it requires some practice). Then you can just tilt the terrain mesh or something to create a slope.

The only problem with terrain meshes is they produce a LOT of polygons. So, outside performance may suffer. Something you could do alternately is make a flat ground, surround it with something (like a wall or whatever) and make a sky texture that looks like mountains. You'll get a similar effect without the performance hit.

yea, it happens. Your best bet is really to make your own textures. It's really not all that hard. I never quite got that far in my tuts though. Anyway... have you played with manipulating textures yet? Y'know you can resize them, scoot them around and angle them on your brushes. Sometimes making them really large helps eliminate the repetitive factor.