IE9 is nice, I love the Windows 7 integration. I really feel like MS is on a roll with their consumer products. I think Windows 7, Xbox, Kinect, and WP7 are all stellar products. WP7 definitely needs some iterations and they obviously aren't coming fast enough right now.
I don't know anything about the phone, maybe someone else can fill you in, and I already gave you my thoughts on what you should look for in general, but let me get a bit more specific.
Last year, I had all three major phone operating systems. iPhone is fantastic, there are no two ways about it. It deserves a ton of credit for what it did to smartphones, and Apple has made key improvements throughout its lifespan. As a blanket statement, and without knowing anything about a person, I would recommend an iPhone to them if anyone asked about smartphones. I left that platform for various reasons, but mainly from sheer boredom, for as much as Apple has improved their software, the interface has remained the same the entire time. Perfectly understandable from their end, but it grew stale for me after almost two years of usage.
Android adds widgets, customization, and flash to the formula. It's a good iPhone replacement for the most part, but it does lack refinement, it lacks cohesiveness, and it's in many cases frustrating to use. Most manufacturers load it with custom UI's that just slow the phone, and you can mitigate that to some extent, but its still annoying. You can find alternatives to just about anything, but (imo) very few things feel complete or as refined.
Most people would do equally well with either of those platforms. Then there's WP7. It is better integrated than Android or iPhone in terms of core apps (Music, Contacts, Games, Pictures) because it leverages Zune, Xbox, Office, and the cloud. The OS has the cohesion of iPhone, with additional functionality in what the icons can do, without actually having the full functionality of Android. Still, it's a new platform and therefore has some maturing to do before it reaches important feature parity (mainly multi-tasking and html5 browser). Even for those of us who knew that going in, the wait for updates is excruciating, mainly because of random bugs that are typical for any 1.0 product.
One more thing, hardware is simply not as important as software in smartphones. Fancy specs are, oftentimes in Android, wasted on old OS builds and crappy UIs. If you go iPhone, you wait for the latest version, if you Android, you go for the latest OS build, and in WP7, you go for your favorite form factor (if you have options). FWIW, I get pissed at MS for the slow updates, and then contemplate sticking my sim in my Nexus One (running gingerbread). But I just can't pull the trigger yet, and that says a ton about WP7.
