Greetings...
First, I think that Phineas' maps are great. Now, on the other hand, I also have liked some of the WotC maps. That great temple/citadel was lovely. However, I think maps should be simple, and easy to read. They shouldn't be colourful pieces of art, unless the 'colour' conveys some sort of information. Also, for quick and easy mapping onto battlemaps or even graph paper for the players, it should be easy to read.
Now, some people will quip, "Isn't it nice that all the dungeons conform to graph paper, or all the dimensions are 5' or 10' increments." But it's just that. A quip, a joke. In the end players don't go around complaining about these things.
I like the idea of occationally making maps a little bigger than the confides of a battlemap, just to keep the players on their toes.
But, at the end of the day, if a map I find online, or somewhere else (I used to use old Doom maps and other video game maps) don't make things easy for me, then why bother? If parts of a map are usable, then I will use them, and disregard the other parts. Drop down a map in front of the players and say, "This part of the temple is in rubble."
Another trick I like to use...which keeps my battlemap in mint condition, is to draw all my maps on acetate sheets. So, when the players come to a new session in the map, just put the new acetate sheet down. Quick, easy, and you can still see the lines of the battlemap underneath. I also will sometimes just draw something freeform down on a large sheet of paper, or a chalkboard I have, and then throw an extra large sheet of acetate I have, that has grid lines drawn on it, in permanent marker. I also used to use a blackboard/chalkboard that I had drawn grid lines on in black marker, which turned out remarkably well.