I agree that MBP Unibody ( I don't have older one ) does extremely slow in charging. Please remember that lithium-based battery are quick in charging up to 80%. The last 20% perhaps can take up to 40% of charging time. However, in MBP case, even the first 80% is slow.
In my Thinkpad (IBM/Lenovo), I usually set 80% threshold to stop charging. It wears the battery less as no need to charge the 20% if we plug in and out the AC frequently.