Wow............. the knowledge here is overwhelming. I checked out their (Garmins) Topo at their web site.......... the first thing I noticed is that it really did not do a good job at showing bogs or small ponds. I will probably get it (TOPO) though. The city street maps you mentioned also sound quite desirable but at the moment (and I'm still learning) the current Mapsource I have, set at the highest detail setting, seem to fill the bill. (I don't see myself caching in NYC but I do work there)
Thanks folks
Brian
Plain ole Garmin GPSmap 76