Well not a particular position, but I love finding veteran players that have always had great percentages and ratios in part time / platoon / or due to injurt shortened seasons. Or up and comeing young players who finally get their first season of 550AB's.
K-Rod is probably a house hold name going into this season as a closer. Before this year he was a great value pick in roto leagues for savy owners to buy cheap or real late in the draft and essentialy have 15 starts worth of 1st tier pitching numbers after his 84INN 4W's 12S's 123K's 1.821ERA and 1.000WHIP
Mark Lorretta was no surprise to most fantasy veterans even before last year going way back to 2003. I dont think even most of the super optimists anticipated last year's break out, but he was considered a draft steal as many predicted they could and did get him late in the drafts.
David Ortiz broke out huge last year. I wasnt a believer (pity me

) and saw him going anywhere from the 8th - 12th round of snake drafts.
This year for a few heads up value picks.
Todd Walker - 2B Cubs. I am still seeing him rated outside of most peoples top 10 2B. Look for .280AVE 90R 20HR 85RBI batting with the protection in that lineup.
Bartolo Colon - SP Angels. Had a rough adjustment and most owners were dissappointed and turned off bye his NL to AL 1st half drop in numbers last year. He found his stride after the all-star break and you can probably expect close to his 2004 post all star numbers like last year's 16GS 12W 4L 104INN 82K's and 3.83ERA.
Well there is no particular position I'm good at, my favorite is finding players who's name recognition has dropped due to platoon situations getting a shot as the every day player and 550+ AB's.
"Son we would like to keep you around here but were trying to win a pennant this year."