Okay so I just beat Misty with my level 26 Charmeleon and level 26 Mankey. I have been contemplating catching a Dugtrio or a Diglett, would this be a wise choice? It's been a while since I've played a Red version of any kind and I don't remember.
I found Diglett to be quite useful, especially against Surge. Immune to Electric and Attacks are Strong Vs. them, win-win. Plus, Dig is just plain awesome so far, assuming it one-shots the enemy. Even then, being able to dodge an attack helps, depending on what attack it was. It didn't seem to take too long for him to evolve either, so that's two more entries in my Pokedex, another bonus. Dugtrio has pretty good Speed also, so being able to use Dig before they get a move off is very likely.
You can buy the Dig TM when you get to Celadon, but I fought Surge as soon as I could, so it wasn't really a viable option then. Can't remember if I had any or many before then, off hand. I made it a point to catch every single Pokemon that I could and even evolve them if it was easy enough, just so I could find see their potential and to raise my Pokedex rank for Oak's aides and such. Kind of wish I didn't bother since I now realize I can just catch some of those evolutions later, but meh, too late now I suppose. :T