Hard to say without knowing your scoring system but I'll take a stab at it.
Hightower = TD's but not so many yards.
McGahee is a tad undervalued right now, but it looks like Rice is the guy right now in Baltimore. I would expect to see McGahee to end up more like a Chester Taylor type RB this year.
James Davis - Huge upside but will likely have a slow start in fantasy terms. Will be much more valuable down the stretch as it is the opinion of many (including myself) that he will get the majority of the workload by midseason.
Mike Bell could be a flash in the pan. He's going to get some points right away but once Pierre is back then he's the #3 guy again. Not a good pickup for the long haul unless P.T. goes down for the year. O.K. if you just need someone to start in week 1.
As to your WR question I have a similar problem myself, but if I were you I'd hang on to Avery. Somebody has to catch passes in St Louis.
I took a stab at yours, can you take a stab at mine?? - viewtopic.php?t=444866