The performance metric that counts is the amount of RAM on the device. "Droidtards" have real multitasking, so they can switch between web-browsing (while it's loading) to pull up their playlist, pop over to a remote desktop window, jump back to their picture album, etc etc etc, all without causing disconnects (with the webpage or remote desktop), nor having to page RAM to/from the flash storage. Without this multitasking ability for iOS, they don't need to load up iDevices with more than their 512MB allotment. (iOS has limited multitasking for i-branded apps only, so yes you can play your iTunes music while surfing, I know).
Now, how to power all of these things, plus anything else that might come up in the next year or so you own the device? A quad-core chip should do it. Since the platform is threaded as a standard (unlike the Windows environment of yester-year), all 4 cores could actually get used. Zipping around on a single core with a 800x600 screen (or worse, the phone you cited) won't see much of a performance bottleneck (CPU-wise) with your apparent workload. Mine, however, makes even 1GB RAM dual core chippery fall over (props to the Galaxy Tab 10.1 for handling it best though). We'll see if the iPad2S can top what we can pick up today with the Asus Transformer Prime.