What I've read on creatine, at one time, was that the water brought to the cells due to the excess creatine, makes the volume of the cell larger, and stretches the outer fascia. This creates tiny little tears in the muscle and smaller satellite cells come to the aid and "patch" the tears thus making the cell thicker/bigger a little at a time. Keep in mind, the effect is not going to be like slapping a t-bone on your biceps...but over time they should show some type of difference visually.
For better pumps in the gym, yeah I've had them when you load up on crap. Nothing like eating a couple In & Out 4x4's and getting all that sodium in you and once you digest all that beef, you slam weights like you're a titan. Personally, the best pumps I get are from having essential amino's a la Milos.
Mindspin had some protein pills that were killer in regards to giving you a pump. He got them from Dr. Scott Connelly and I was privileged enough to try them for about a month. Unfortunately, they most likely aren't ever going to be mass produced, and I was only able to try them that one time.
