My usual for doing egg salad follows most of the suggestions already proffered.
I've always had a fondness for mustard-tasting egg salad, so use a reasonable amount when making mine. Recently spiced things up by using a bit of Malle dijon mustard along with the regular old boring yellow mustard (like French's, although I have a slight preference for Plochman's). Gives it an extra tang.
Then just to taste with salt and pepper and round it out with mayo. I don't make my own, so I use JFG brand (localized brand in our area that is fairly "eggy" tasting to begin with). I don't really have a percentage mix of mustard to mayo - maybe 1/3 mustard mix (the dijon/regular yellow) to 2/3 mayo? I just kinda spoon in until it looks right, and do lots of taste testing along the way...
Oh - almost forgot. I'll also add in a dash or two (depending on batch size) of Worchestshire sauce (did I spell it correctly?) and often a pinch of sugar to round out the extra spice from the Malle, and the W. sauce.
Most of the above is how my Grandma used to make hers, so I obviously obtained my preferences honestly (although the dijon mustard part is my own just to add even more mustardy-zip).
But, one thing that I bemoan . . . my Grandma had an excellent two-bladed curved chopping mechanism that she used when doing the chopping of the eggs (which she always did in her hardwood bowl, another implement that I don't have). The device (which my dad now has so I occasionally visit my one cherished kitchen implement from my Grandma's kitchen [well, I sorta lie... I got her elderly egg cooker!]) is sorta a single handle version of this:
http://store.everythinghome.org/7doedmikn.html
with wooden handle and smaller-ish sized blades. But, still curved to fit the shape of a bowl. Since it was single-handle, easier (I would think) to maneuver around the bowl that this fancy Henckels version. Especially if you are using your other hand to hold the bowl! Guess I need to do a little web search to see if I can find a good replacement...
Thanks,
Mike