Router for QoS over public internet?

I have an Asterisk box on a static IP with Time Warner cable and a SIP provider for my DiDs. The same internet connection is used for calls and for office email/browsing. I know there’s only so much QoS one can expect using the public internet, but from what I’ve read it seems that using QoS on my end can help to some extent.

Any experience with QoS results or suggestions on router make/models would be helpful.