Not really. Swap in UNIX is equivalent to the pagefile in Windows. My own root partition is one gigabyte, and 34% used. But my /usr/ partition is 10 gigabytes, 50% used.

How much you need depends on how much you use. So it's hard to say. That's why UNIX is organized as it is with /usr/, /lib/, and the like. You dont' have to throw everything into /. Just the most basic system stuff the system needs to start itself belongs in there, the rest can go in other partitions mounted on those base folders.

It also lets you expand things without having to replace and reformat, because you can put partitions wherever you please without worrying about changing drive letters. 500 megs should be lavish for a bootloader. You can get by with a tenth of that but there's no point making it tiny either if you've got room to spare. How much you need depends on how much you use and how you organize it. If you make /usr/, /lib/, etc partitions, you don't need a huge root. If you're just jamming everything into / however, you need a big root.