WOW, you are lucky! I bet you have a very happy toddler! When my son turned 9 mos. old he began taking one nap for nearly 3 1/2 hours...he was a joy!!! Now he's 2 1/2 years and takes one pm nap for 1 - 2 1/2 hours.
However, my 9 mos. old daughter cannot survive without her am and pm nap of a couple hours each. I think it truly depends on the child.
Lissa, Does Oliver sleep well at night? Or at least COMPLETELY through the night?
If not, that is major indicator that he may be sleeping too much during the day...however, when they get in those growing spurts there is no stopping those naps- let them sleep...they grow when they sleep!!!