I don't think memory's the bottleneck on most modern systems, so it seems like Google made the right choice by allowing greater memory usage in return for better end-user performance.
You're right in that Google's made excellent engineering tradeoffs to keep Chrome snappy, but note that memory is, sort of, the bottleneck on modern systems. Specifically, the channel between memory and the CPU:
I'm not sure exactly why this happens, but it does use a lot more memory than you'd expect. Right now, I have 13 Chrome tabs open, Mail.app, a Terminal session, Colloquy, and TextWrangler running but with no documents, but it has 1.14 GB wired (as in, can't swap) and 1.66 GB active. That's a total of 2.80 GB memory in use.
But also, it takes a while to swap (upon which it beachballs all over the place), and it's not very intelligent about when to swap.
It's a 2.00 GHz quad-core machine, so I have plenty of CPU power. It's just that when I get working on more than one or two things at once, switching between them swaps everything to heck.
