Eric Davis in his prime is probably the best comparison I can think of to Trout this season. I really have no idea what kind of power or steals numbers Trout will put up in the next three to five years, I see people saying he's a lock for 40 and should push 50 steals a season for awhile, and that his power looks to be legit enough to bank on at least 20. Davis stole 80 bases in 1986, at the age of 24. Trout seems to have that kind of potential, especially for a guy who could hit .300. I'm not expecting his numbers to improve right away but if anyone has a shot to be unique to a club it could be Trout with a 30/60 year and a possible .300 average to go with it.
And before anyone says it won't happen, hes got 160 MLB games under his belt now, and has 32 home runs and 61 steals. His K% rate of 23.8% make me a little less optimistic, but Davis struck out just as often with 25.2% k rate in his prime years (1986-1990). He's probably more of a .280 or .290 hitter assuming his power doesn't vanish, his speed will keep his average above most players who share his K% rate.