Thanks to Jerry for posting about Gmap4. I am the developer.
Yes, if you ask Gmap4 to display topo maps that are hosted by the MyTopo Company (which is owned by Trimble as of 2011) then you will see topo map 'tiles' that each has a heavy watermark. Also, Gmap4 is required by Trimble to display the MyTopo ads. These topo map tiles are medium resolution.
But wait - there is a better option.
Gmap4 can also display high resolution topo maps from a different source. These maps do not have any watermarks and there are no ads. Here is the same link Jerry posted but with the hi-res maps. The only difference in the link is that I changed &t=t2 to &t=t4:
The higher resolution topo (with variable hill shading) is simply stunning.
I have posted about Gmap4 over at portlandhikers.org and I think you will begin to see that bunch start using the higher res topo maps when they embed Gmap4 maps in their forum posts.
If the admin here at BPL wished to allow it, there ought to be a way to embed 'live' Gmap4 maps in this forum also.
Yes, both Hillmap and Gmap4 let you do trip planning and produce a GPX file. We each implement this feature in a different way. Pick the one that best suits your needs. To the best of my knowledge Gmap4 gives you more control to tweak *every* piece of info that goes in to your GPX file than any other software out there.
To start trip planning with Gmap4, click Menu ==> Draw and Save
For more info, visit the homepage and download the Help file.
Then search the Help file on "Make a map with Gmap4"
Gmap4 homepage: http://www.mappingsupport.com/p/gmap4.html
Joseph, the Gmap4 guy