I don't think you get into problems with FAT32 either, if you don't want to change by other reasons. FAT32 is the most compatible one at least if you're going to use it in "obscure" machines.
I have even 2TB external HD formatted to FAT32 for backup use, and couple 1TB drives too, and so far they have worked
And many bigger than 128GB external drives also come pre-formatted in FAT32.
HFS+ is the most unlikely to get write support in "alien" systems, so I wouldn't use that at least...
