Bart,
Congrats on the iPad ownership - especially at the price! ;)
I've had mine since start of April, and it's used for hours every day. I've been collating comments on iPadThoughts.net, both gushing and negative.
Biggest iPad disappointment is the lack of good magazine / newspaper Apps - I really wanted it to provide me a way to read this content, and so far nothing works right, or is priced right!

Some iPhone Apps do scale OK, games in particular ("Super Slyder" for example).

In iBooks, keep tapping the "bigger A" to increase text size - you can go to a HUGE size. My biggest issue with iBooks is the lack of books available.
I'm trying Amazon and B&N, but both throw you out to the browser to shop/buy. Not so tidy.

BTW, I found on my iPad that the App store loading times massively slowed down when I put all my (20,000+) photos on the iPad. I wonder if you see the same effect (if you're loading it up, that is)