YES. You may need a new cable. There have been bum cables reported where they would charge but NOT do data (one couple both got 2 bum cables).

2nd, I've sometimes noticed I have to slide the nook login screen before my Mac sees it, don't know if that's normal.

Yes, that sounds about right. It charges just fine in the wall outlet, but will not work at all on my computer.

Last night I went to transfer a book with ADE and didn't see the nook even after restart of ADE. When I did "slide to unlock" I got the pop up on the nook it was in transfer mode and it popped up in ADE. I've not done a lot of transfers to the nook to say if it always worked that way. The nook 3G automatically goes into usb mode when you plug in, but it doesn't have the slider thing to unlock either

Hey, I have a MacBook Pro, too. It was frustrating at first until I realized the problem. Here is what I have found: After you have downloaded Adobe Digital Editions, (and kept it open on your desktop) plugged in your nook, and downloaded a library book, some folks are reporting that the nook is not showing up under the bookshelves on the Adobe Digital Editions software. Try this:
1. You should see Nook listed on the left side at the bottom of the Adobe Digital Edition. If you are asked to authorize the Nook, authorize it.

2. If you don't see Nook listed click on Library view on the top left hand side. It should appear as a bookshelf. If you don’t see it, it is likely that you have an adobe digital edition already on your nook and you will need to take that off. Here is how you find out:
a. Open the nook icon. You will see folders. Adobe digital editions will appear as its own folder. Click on it an delete it.

3. If you have a mac it is possible that you can’t see the adobe digital edition folder. Plug your nook into a pc, open the nook icon, find the adobe digital edition and delete it. Then eject your nook from the PC and plug back into your mac and you should be good to go.

4. Once you see your book on the right hand side and the Nook listed on the bottom left hand side. Click on the book and drag it to Nook. Wait until it is copied fully, as indicated by the progress bar.

5.. Unhook your Nook (remember to eject not just drag to trash) and go to My Library on the Nook then to View My Documents. Scroll down until reach the book you just copied. Click the circle symbol on the touch screen of the Nook.

If you need some troubleshooting with ADE check these steps out:
nooktalk.net/how-to/troubleshooting-help...th-nook-or-nookcolor

But I think your problem is cables man!