I can see what you're trying to do SeaGS but sadly loading every waypoint from every database won't work, as there must be literally thousands in Kevins posts alone, and I'm sure that 500 is your limit.
HMR has alreay mentioned it, but IIWY I would have one "Master File" on your PC with different categories eg one for Burger King, one for McDonalds, one for lap dancing clubs, class wine bars, English Heritage sites etc etc etc, then when you plan a route say London - Paris you cherry pick the waypoints from each category in your Master File that are close to the route you're planning, and save that as a separate file. (Don't forget you can have a max of 16 categories). Eg, there's no pint clogging the unit with every Burger King site in the UK when probably 95% of them will be nowhere near your route. A waypoint in Lands End is of no use to you when travelling from London - Paris.
By default I think that all waypoints are stored on the computer alphabetically, but by clicking on the top of the relevant column this can be changed to North / South. Then using your "Ctrl" button and clicking on the waypoints, you can see highlited which waypoints from each file you need to copy and paste into your London - Paris file. NB. The first waypoints to set are always "Home" and destination
and always
copy and paste, never cut and paste. So you may copy and paste say 30 waypoints from the Burger King category, 45 from the McDonalds category etc.
After a trip, the first thing I do is to download from the unit to the PC all the tracks and waypoints (there are almost guaranteed to be new waypoints you've picked up on your travels) delete the ones you've already got (so leaving the new ones) give each one a category, re-name it if necessary and give it a symbol then cut and paste the new waypoints into my "Master File". It works for me anyway.
, either for eating shite at Burger King or trying to put all the waypoints into your 2610 
