When I pick a pipe to buy aesthetics, dimensions, weight and price are all equally important. Dimensions and weight, for me, are pretty narrow as I clench more often than I don't so I prefer smaller lighter pipes. Price can vary widely depending upon if I want an out and about pipe or a 'best' pipe. As far as aesthetics go, I much prefer sand blasted pipes but not because of their tactile nature but because I find them interesting to look at, whilst I can appreciate grain apart from birds eye I find grain a little boring and plain.
When it comes to choosing a pipe to actually smoke now the choice is easy, I choose the pipe that smokes the particular tobacco I want to smoke best. When I buy a pipe I smoke various blends in it, if it doesn't sing with blends I like to smoke it or smokes poorly for me then it gets sold on. I want a small rotation of good quality pipes not a massive collection of pipes I display and don't smoke.