Hi,
depends on your usage.
/boot is the default (~512 MB) ok - if you never delete old kernels you get perhaps trouble in later times.
/root is 10GB enough, but I would start with 20GB (if you use LVM (the default) you can easily expand the space later).
If your maschine use swap you will have an real problem (performance). You should not overcommit RAM and I would guess you run well with 4-8GB swap-space.
Udo
