Personally I far prefer sprite graphics to so-called photorealistic 3d. They have more character and charm. 3D is just somehow lacking any soul.
If stuff has to be 3d (which it seems it always does now) then I prefer the stylised look of something like TF2 over the real look of HL2.
If stuff has to be 3d (which it seems it always does now) then I prefer the stylised look of something like TF2 over the real look of HL2.