What type of connection?
The 7200 will give you better control of the traffic however will be quickly overwhelmed with GigE of throughput -- Generally not a good choice for high speed inter-datacenter links.
The 3750G has better throughput but limited QoS control -- not a good choice either.
For the best low end cheap solution you might consider the 3750-Metro -- great throughput and good QoS control on its uplink ports.
For the best of the best options -- go with a 6500 with SIP/SPA. Tons of throughput, tons of QoS control options, tons of flexability and investment protection.
Hope this helps.
Please give this post a quick rating :)
Thanks,
Brad