I use the following:
/swap - same as my RAM, which I believe is the recommended amount
/root - 10 GB
/home - whatever was left on the drive (I believe it was 18 GB)
With 10 GB for root, I haven't run into any disk space issues yet, but I don't plan on using more than one desktop environment. I've added the KDE game pack and some other assorted programs and added one of the newer kernels and believe I have near 5 GB left. I'll check when I get home.
I only used the smallish 18 GB for /home, because the system is single user and I didn't want to give up my Vista partition quite yet. I haven't moved my music collection over yet, but it's only 3 GB any way. I have a Blu-Ray player hooked to my pretty sweet TV, so I don't plan on ripping movies to this computer, so I doubt I'll need much more space that that. But probably at Christmas time I will get a new laptop with Win7 on it and dedicate this laptop to Mint fully and start to explore the multimedia capabilities.
I don't see many recommendations for more partitions than that anymore. Used to be you would see guides insisting you have a /var, /usr, /bin, etc partition. Somebody will correct me if I am wrong, I'm sure.
I like poetry, long walks on the beach and poking dead things with a stick.