In an ideal world, I would know 3,000 programming languages. And when faced with any task, I would open my Rolodex o'Languages (with all of which I am quite proficient), and merrily flip through it to find the perfect tool to solve my current problem, mumbling to myself "Ada? no... ALGOL? no... Applescript? no... ASM? no... AWK? no..."
Half an hour later, I would leap from my chair, exclaiming "The right tool for this job is a combination of UNISAP and PACTOLUS, with just a touch of ASDIMPL and XPOP!" And it would be the perfect tool for this job, and I would whip up an elegant, simple bit of code which efficiently solves my problem while being readable and easy to maintain.
In an ideal world, you'ld know only one language; one that was expressive, powerful, high-level, and easy to read. Everyone would use it. Performance wouldn't be an issue, because the language would have a mythical self-optimizing compiler that could generate faster code than the best hand-tuned assembly. It would determine intent, and re-write your algorithms to equivalent, faster algorithms on the fly. It would sort lists in constant time, chop onions, and make jullianne fries.
While you're dreaming, dream big! :-)