One of the things I miss most from my Blackberry Bold 9000 is the hardware keyboard. The touchscreen keyboard in CyanogenMod 7 is nicer to use than the stock HTC keyboard on the Inspire and Swype is even better for texting than that, but nothing compares with a hardware keyboard when you want to mess with the terminal or play with emulators. I really wanted a phone like the Desire Z, but since the Inspire was only a $70 upgrade I decided not to wait longer for a decent Android with a keyboard to be subsidized by AT&T. Instead I've bought a Bluetooth mini keyboard to use with my phone. The stock Sense ROM the Inspire ships with won't support Bluetooth HID devices, but CyanogenMod will! That's one of the reasons I decided to root my Inspire and install CyanogenMod 7.
Setting up the keyboard was a bit difficult because the manuals are not very helpful, but the reviews on Amazon helped me a bit and I even wrote one myself after I got my keyboard working. Pairing the phone and keyboard in my case required pressing the discovery button above the 9 key then entering a number on the phone and the same number on the keyboard, then pressing enter. This step was what I got stuck on for a bit, I'd press the discovery button and the phone would find the keyboard and ask for a number but be unable to pair with the keyboard. You need to enter the same number on the keyboard and then press enter, I had to read the manual for Windows Mobile on the CD to find that out.
While it's not as nice as a slide-out keyboard built into the phone, this Bluetooth mini keyboard is great for emulators and games that otherwise requiring using an onscreen gamepad. I've got GENSoid setup with mine, using wasd for the d-pad and jkl for the abc buttons. It's great to be able to play Sonic the Hedgehog at a table when I'm out of the house and bored. The Ur-Quan Masters port for Android also works much better with a hardware keyboard, not to mention writing notes and long emails.
EDIT 9/10/2011 - If you don't want to mess with rooting your phone and installing a custom ROM you can try out this Freedom Pro Bluetooth keyboard that includes the SPP profile as well as Bluetooth HID. It may or may not work on your phone in SPP mode. It's worth a shot if you really don't want to risk bricking your phone.