I guess it depends on how many BGP routes etc your gona have... since you an end user and Not an ISP I would suggest a 2600 series ( replaced by ther 2800 I beleive ). We use these on our MPLS network and they RUN BGP fine, with about 80 routes.
We also use 3725`s on our internet connection, these use BGP but only to advertise out 1 Subnet into BGP and also it learns a default route.
It al boils down to how intensive your BGP is going to be..... Im sure someone can back me up with a more technical followup.....
LEEroy
MCNE6,CCNA2,CWNA, Project+