Works perfectly with Win 7 ( fingers crossed as I write this ).
MapSource works well enough for me in the Wine emulator. (BaseCamp doesn't run under Wine so far.) Both run well enough on XP-SP3 in a VirtualBox virtual machine, but I haven't fully tested interaction with the GPS. Wine and VirtualBox allow me to make multiple copies and clones of existing machines so I can experiment without risking a working copy.
I also use GPSBabel to transfer waypoints, routes, and tracks to and from the Linux host machine. (GPSBabel, MapSource, and BaseCamp all read and write .gpx files.)
(MapSource builds maps into a tmp-file and then copies the file to the GPS very slowly. One can speed the process up by copying the completed tmp-file, aborting the transfer, and then manually copying the tmp-file to the memory card. The file name must be Garmin\gmapsupp.img for the 60CSx (only this file will be seen by the GPS) and Garmin\<filename>.img for the 62 series (multiple filenames allowed--I use names describing the map).)
What's more troubling is Nat'l Geo discontinuing it's TOPO ! software and support last year. For me, the interface between the GPS and NG software has been close to flawless for a long time.
I bought the pre-internet version (the maps are on the CDROMs/DVDs), it will live forever (or as long as I want it...). It also runs under Wine (and likely under the VMs) but I haven't tried it. It also reads and writes .gpx files.
At Doug Paul's suggestion, I bought a second 60CSx that was on deep sale as a backup years ago. DP actually called me from the store to tell me there was another CSx there, on sale and likely had the SirfStar chipset. Still owe DougPaul a tip of the hat for the heads up. When the existing, overused and beat up CSx bites the dust, the other one comes in behind it.
I also bought a spare (before I called anyone else...
). The new one also has some improvements: increased battery life and it can use lithium batteries.
Newer GPS receivers may have different (hopefully improved...) features and user interfaces and better accuracy through multiple GNSS systems (eg GPS, GLONASS, Galileo) and/or multiple frequencies (two or more of L1, L2, and L5), but the current 60CSx and 62 series are good enough for hikers in pretty much any likely situation.
Doug