In the process of making a mod (that I'm never going to finish at this rate), I made a change that I'm quite enjoying on a standalone basis: A slightly revised monsters file. See the link below.

There are four changes: All the monsters have double their original hit points. Killing them is worth double their original experience points. Most of them give slightly better treasure (one level better, with the probability increased by 5%). And I've renamed the three types of Tree to Tree, Treer and Treest (to make the distinction clear and to fix bounty hunt confusion).

I've just played through it nearly twice with this file, and it keeps the game a little more interesting.

Because of the better treasure, I've disallowed myself any looting exploits, such as multi-looting, Mephistoing, store reloading and Enchant Item reloading. (Do the latter two count as Mephistoing in the local parlance?) But play it as you like to.

Oh, right. Installation instructions. Insert the new monsters.txt file into your events.lod file, using (for example) St0rmCat's MM7View. Remember to export and backup your original monsters.txt first. (If you screw up, here is the href="http://www.blimix.com/mm7/OrigMons.txt">original.)

I have no idea whether this will work with all versions of the game. It may well not work with non-English versions, as the file contains English monster names.