The thing I can't take about stock is just that...it's stock, it just sits there w/little or no change for months or (in the case of the D2) years. No new features, functions...boring and limited.
My wife is a "stock ROM" kinda person...very happy w/the stock ROM, basic functionality, stonehenge-like immutability. The fewer changes the better.
I'm a custom ROM kinda person - love the regular updates/new features that they provide, particularly CM7 with its nightly builds that you can get into if you want. Things like my favorite feature on CM7, a setting that removes the need to hit the OK button after putting in my PIN...and enhanced lock screen time-out options, options to turn off the lock screen entirely when you have a PIN set, enhanced LED control, etc., etc.
That's what I like about Android...you can choose your own experience, find your own smartphone zen. So cool.