Im pretty sure any issues with connecting larger drives are a matter of formatting, ie usb sticks are generally fat32 and larger drives are generally ntfs. you can re format your external but that would meanremoving all files beforehand then moving them back, then after that im not too sure your pc would like the drive. Ive been running a 16gb usb without any issues but my tab recognizes usb hard drives as blank usb devices. Also any drive without external power wiol not run because the adapters for galaxy tab at least dont put out power.
smeggm and chaeoss91 - glad you both decided to join us here!
chaeoss has a great point. Honeycomb 3.2, 3.2.1 and ICS 4.0.X have support for FAT32 and NTFS. Other formats (ext3, ext4, ext5, exFAT, HFS) may not be supported. Also, I have found some USB drives that require more power (2 USB ports, one for power, the other for data & power) do not work well with Android. Lower power devices (SSD's) should work.
I have a 32 GB microSD (NTFS) and a 64 GB SD (NTFS) mounted in my TF101 in addition to the 16 GB of internal memory. I have used a 1 TB Porche external drive with no issue as well, but it is a low power design.