Yeah what took you so long, generally it's the bitter ex N900 owners that reject the N9, knowing it's heritage.
There was a N950 on eBay for GBP325 a few days back that you missed, damaged but usable screen though, I assume it was actually sold.

Apps wise look for (I think there's an actual thread for this but anyways):

• Filebox.
• EasyList.
• The Flashlight.
• Meecast.
• Nano.
• N9 QTweak - most of the tweaks you could think of in one place, but read manual should install catch apps through N9 QTweak so that you don't have to worry about 5x download limit in Nokia store.
• Opptimizer - if / when you get the urge to overclock.
• Conky.
• Battery Usage.
• Call recorder.
• Call blocker.
• Firefox (for flash).
• Opera (for full desktop experience minus flash).
• Homescreen settings.
• CuteTube.
• Open video player.
• Phone Counter (never rely on sneaky networks for your call / data usage 24-48 hours late again).
• Easy Debian!!!

Apart from that, make sure you set up track and protect, I highly recommend finding some relevant RSS feeds to take full advantage of the feed screen, I never used feeds before having an N9 but have never looked back.
Maybe search the forum for customisation ideas, operator logo, boot video, homescreen settings backgrounds etc.

Any of the above apps you can't find in the Nokia Store are probably located right here on TMO, speaking of app stores, try N9 Apps, and Apps For MeeGo.

This is in no way an exaustive list of good apps, just the notable ones i picked out that are installed on my phone.