I recently decided on the Garmin Legend C for my first unit. I plan to use it only for geocaching and bicycling on trails. I was steered away from the Vista by a salesperson who questioned the quality vs the cost of the extra functionality. I found the Legend C for right at $200 online. I am very happy with it so far, even though I haven't been able to get out for a cache yet.
As far as the memory is concerned, I guess it sort of depends on how big an area you are interested in keeping on the unit for regular use. I have loaded TOPO maps for the eastern half of Wisconsin plus the northeast corner of Illinois (everything east of I-39 and north of I-80), and have not reached the 24meg memory limit yet.
I don't have any knowledge of how much memory the metro guide or city navigator may use. I have seen other posts about that though, so you could look through other threads to get ideas about that.
