Sorry if I came off as a complete realist, and thank you for all the great posts. Sometimes I do feel that terrain is neglected as a gaming topic. Most of us collect armies, and discuss tactics and lists, but terrain is probably more seen as a facilitator, and most of us probably strive for a fair terrain setup so the armies can slug it out. Funny Scotland was mentioned, I was going to use Edinburgh's Arthur's Seat to contradict myself as a prime example of hills being Irish (even in Scotland) next to Gothic buildings.

When I play Epic, we mostly follow the Tournament set-up procedure with 12 pieces of terrain etc. I do realize that for a pick-up game, it is a good solution. I use the same solution for area terrain as Bissler does, a flat "base" which shows the exact limits of the forest for gaming purposes, and then token trees that can be shuffled around without impeding the troops' advance, or needing to balance them against fixed terrain pieces.
Example of Tyranid infested swamp for my ongoing Tyranid terrain project:

But I live in Sweden, and if it is not a building or a mall or a field, we have plenty of trees. Living in the outskirts of the capital, I do notice that the few trees that are left mostly occupy unwanted land (expensive to exploit).
I lived for a while in Japan, and Japan is extremely rich in forests, but only due to it being extremely mountainous (and a shogunate who banned logging to stop increasing land erosion). When you travel in Japan, you'll quickly see that if it there is any flat land, it is appropriated and used.
That is why I named the thread "Observation". It was simply that. I do not think things are more "right" or "wrong", but I do believe in mixing things up and trying out new things, and I used the hill/forest example because I found some war gamers' knee jerk reaction interesting. Terrain usually comes in every possible flavour. I also think the comment on abstraction relevant. Movement rates are better thought of as abstractions of getting from A to B, not velocity. My memory from serving in the Army (in Sweden it used to be mandatory for men, optional for women), is that getting from A to B generally involves lots of map-reading, intelligence, recon and choices. You tried to follow paths and minor roads as well, since walking over a field or through a forest generally is not like a walk in the park, so you sort of zigzagged your way forward (roads themselves generally following land boundaries).
One idea I have right now, is to have a third player set up the board in advance, take pictures or draw a sketch beforehand, and send it to the two players who can choose forces accordingly. It would be like two Supreme Commanders picking forces for a key battle. City board, full of woods, desert with dunes etc. This would perhaps see some forces never being picked suddenly getting a chance. A terrain-filled board would favour infantry, which also would favour anti-infantry vehicles. Since AT is generally harder to obtain, people generally go for AT options (Predators, Razorbacks, Hammerheads etc). A desert battle with dunes could make for an epic tank-battle.
Thanks for all the comments. I spent a good day of the morning reading them.
/Fredmans