Does size really matter?

[RecklessEnthusiasm]

For me, it is just a matter of keeping in mind the ultimate application of the map. How big is it meant to be viewed? After you know the intended size, then you just need to figure out the resolution. Print rez is typically 300DPI, screen rez is ...apparently something I don't know, VTT console images are typically 100DPI (though I've seen some folks do 50 or 150 as well).

If it is just practice work, I like to pick an arbitrary "standard" paper size. Then I always have the option of printing it out and having it look nice on a page. I'm in America, so 11x17 works great for most world map projections, 8.5x11 for small regional stuff or, if you are ambitious, 36x24 poster-size for very ambitiously detailed/scaled stuff.

[Hai-Etlik]

screen rez is 72DPI

I haven't seen a 72 DPI monitor in ages. 100 DPI is typical of modern desktop displays.

[RecklessEnthusiasm]

I haven't seen a 72 DPI monitor in ages. 100 DPI is typical of modern desktop displays.

Oh. Whoops!

[jfrazierjr]

if you are ambitious,

And have LOADS of RAM or are very very patient...

36x24 poster-size for very ambitiously detailed/scaled stuff.