Arul's recommendation for the ASR series, should meet your performance/feature requirements. Since you also mentioned "cost effective", the 7304 with NSE-100 or -150 might be worth looking at too. (NB: possible issue, VAM or VSA modules might not be supported. There's a Cisco Catalyst 4500 AGM Encryption Service Adapter that's listed but unknown whether it would provide the features or performance you desire nor whether it's correctly listed to work with 7300s.)
