In terms of overall sight lines and proximity (closeness) to the field, you can't do much better than section 128. Sure, you could purchase the Coors Clubhouse seats with a free buffet and waiter service but that doesn't make the actual game more enjoyable. The game is enjoyable for me if I have decent seats and the Rockies bring home a W. 128 is immediately behind home plate so they're sought after for every game to say the least. I found a good deal on these seats via Stubhub, it was a day time game vs. the Marlins so the game wasn't in high demand. Would sit there again in a heartbeat and so should you.
The "RockPile" just doesn't do it for me, those seats are too far from home plate - I always feel completely disconnected from the game when I sit there.

There are lots of great, authentic and original concession items at Coors Field. I was convinced to try Rocky Mountain Oysters during this past visit. Garbage. They could be delicious, except they were served with marinara sauce.