Obviously, the dimensions must be divisible by 16. But if i don't use Base-2 sizes (ie. 16,32,64,128,256,512 ), but use some other value such as 192.....will my textures end up more blurry than intended? This is the case for map geometry textures, but is it the same for .mdl textures?

Good question, i always wanted to know the answer.

Yes they will. Half-Life with scale the, up to the next nearest power-of-2 size. So if you use 192 it will scale it up to 256.

Most graphic cards *require* textures to be power-of-2 internally anyway.