This was my first Apple product and it took me about 3 days to figure it out........lol
Since you have multiple iDevices I wonder if you did what I did originally, and used the cable you already had hooked up to your compuer?
When I switched to the cable that came with my iPad my sync issues went away.
The easiest way to use an iDevice is to let iTunes be a mirror. Just allow it to sync everything in iTunes and iPhoto and all will be well....otherwise you will encounter problems. To manually sync things you have to tell it you want to manually select items...but you can't go back to sync all after that...it will wipe your device. It's kinda dumb in that respect.
It always has been easily downloadable as PDFs, mine are stored in iBooks on my iPad.
The same holds true for most other manufacturers these days as well, the windows machines included.
Update: Well, I haven't done a thing differently whatsoever, but it now seems to be syncing with no problems. For a while there it would alternately sync correctly, then wipe everything clean with the next "sync." But now I've had at least 5 successful syncs in a row... so hopefully the problem has magically disappeared.
On another note, I've successfully filled up my 32GB iPad in less than 36 hours! Most of that is movies, TV shows, and video postcasts that I stuffed onto it to test the size limit... I really don't need everything on there at once, but I'm definitely happy with my last-minute decision to go with 32GB over 16GB.
I figure by the time I start to regret not getting the 64GB, they will have a new iPad out that I'll need to get and this one will become a gift to my hubby or parents.
Thanks again for the help, all! Trip, I didn't think to check their online manual; thanks for mentioning that. Will take a look through it to see if there are any features I haven't discovered yet!