While, I don't own the iPad, I have tried it out a couple times at the store. Just by using it briefly, I know the screen would give me eyestrain from reading text on it because I can see the grid pattern between the pixels. It feels like it has a lower pixel density than a typical LCD monitor, with a relatively low resolution (1024x768).
The iPod Touch would be good for any e-book reading. But PDFs would be a bit tiring. If I was in your situation, I would buy an iPod Touch to hold me over until the new iPad with a higher res arrives.