I'm sticking to my PSP-2000 thank you very much and I never plan on going to the PSPgo.
I have twenty-four games for my PSP and only two of them are downloaded from the PlayStation Store, Syphon Filter: Combat Ops and Patapon 2 which are both PSN Exclusives.
The other twenty-two games I would have to repurchase again just to be able to play them on a PSPgo... at full listed retail price...
For example, Dissidia: Final Fantasy, now I already have this game but if I wanted to repurchase it from the PlayStation Store it would cost me $39.99.
... Why the bloody hell would I pay $40 bucks when I can go into a GameStop/EB Games and play $20 bucks for a brand new copy... or even $15 bucks for a fully working used copy.
I checked the PlayStation Store yesterday and counted how many PSP games they had: 302, of which 26 of that number are PSN Exclusives, add to that 44 "Minis," and 97 PS one Classics and you have a grand total of 443 games you can buy and download on your PSPgo...
While on the concurrent PSP-3000 you can still buy and download all 443 PSP games on the PlayStation Store if you wanted and you can most likely get the exact same game on a UMD at a discount.
And while yes, having the PSPgo will open up the video section of the PlayStation Store where I can buy and download movies and TV shows that's simply not enough to get me to buy a unit.

Another thing...
Okay, so not counting the PSN Exclusives, which are download only, or the so-called "minis," or the PS one Classics, there are 376 PSP games currently on the North American PlayStation Store...
While I was looking over that list of PSP games, not once did I find a game that wasn't also available on UMD.
There have been over 600 games officially released in North America and yet the North American PlayStation Store only has 376 of them.
And add to the fact that your PSPgo is region locked to the country you set your PSN account to and your missing out on all the games you can import from Europe and Japan that never made it to North America.
Invizimals released Nov 2009, for example, will basically never move out of Europe because it requires the PSP Camera accessory to be able to play and the PSP Camera never made it here even though it's been out in Japan since 2 Nov 2006, and has been available in Europe since 25 May 2007...
The Bleach: Heat the Soul series is another example, that so far has only been released in Japan so the only way we would get to play a game in this series is via importing it...
.... That all said, who here has a PSPgo, and who here has the PSP-3000.. or 2000.. or even the 1000?