Firefox is a pretty solid example. Started slim as hell, gradually pulled plugins in until it was more bloated than IE and everyone moved to Chrome. They realized the problem and have started pulling back (although you could argue the opposite with the new integrations), but it still stands as an example.
If Firefox wasn't bloated, then nearly all of the new value-added features since version 3 or so should have been added as included (and disable-able) plugins: spell check, Hello, the new tab implementation, etc etc