Well first off just forget about Betemit, he has never lived up to his hype.
Burke to me will either be a nice player in the future or nothing at all. He doesn't have much upside there, I can see him developing into another player the Astros have ... Adam Everett.
Nady hasn't been given a real chance to show what he can do at the ML level, especially since the Padres traded for Giles. Which is to bad cause I actually like him. He has no problem hitting in Triple A this year so there really isn't much left for him down there. I thought he might be traded and then get a chance to play but the Padres seem to be doing what the Twins do with their prospects. Keep them waiting. Hopefully they get rid of Klesko and plat Nady soon, cause Klesko is a mess in LF. I like his potential to hit 25-30 hr's hit in the .280's.
Atkins obviously gets some fantasy attention off the bat since he will play in Coors. Been hammering the ball in Triple A this year and has more walks then strike outs. I'm not his biggest fan but at Coors he should be able to hit 30 hr's and hit around .300 in his prime.
Last but not least Phillips, who has been much better in Triple A this year. He is hitting .310 and despite what LBJackel said he is not striking out to much

Through 101 games and 377 at bats he has walked 34 times and only k'd 43 times. He obviously won't have much power potential, but he could get double digits there. One thing that sort of kills him from having more fantasy value is his SB numbers. He only has 10 SB's this year and has been caught 10 times... not good at all
Overall I'd say :
1 - Atkins - gets this spot for his great BB/K ratio and the coors factor
2 - Nady - I think he just needs to be given a shot to start producing
3 - Phillips/Burke - Phillips has more potential then Burke, though Burke is playing better right now
4 - Betemit - like I said.... stay away