I whould suggest a 2924 whould be perfect for the access layer..
But distrobution, once you grow it can get bogged down.
Look at the pps (packets per second) rating on various switches.
From their you should come up with the true speed ratings of various switches &/or routers.
Also I whould suggest a layer 3 switch for the distrobution layer.
If you plan on using vlans or any policy based filtering etc..
Keep it out of your core!
You want your core processing packets as fast as possible, while your distrobution is faced with ACLs/Vlan Routing etc..
You could even step it farther into layer 3 at the access layer.
This whould be very costly thou.
Think and plan ahead
As for the question on most used switch for DC's..
Cisco's 6500 is a very popular choice with good reason..
I think it whould be overkill for you right now thou.