| | Go with 8700 or wait for 8800
I own a BlackBerry 8707v and I use it in Australia. It has a UMTS 3G connection capability, which means it can connect to 3G networks in Australia, Japan and some European countries. However, before you get too excited about a 3G BlackBerry, I've found that my BlackBerry isn't very good at 'falling back' to GPRS when the 3G network has a poor signal strength, which is in a lot of places in Australia.
Also, the Qualcomm chipset in the 8707 device is noticably different in performance to the Intel chipset in the 8700 and other BlackBerry devices. From my experience this affects download and display processing speed, as well as (I suspect) phone call quality.
Overall, if I had to choose between a 8700 and 8707 device I would choose the 8700 for the Intel processor. Factors that might make me reconsider this recommendation are:
if I was going to visit Japan frequently; or
I wanted to use the tethered modem capability of the 8707.
However, data plans for the 8707 from my carrier are so expensive that I haven't used the 8707 for its tethered modem at all.
If you're not in a hurry I'd wait for the 8800 to be released...
I hope this helps.