For standard DHCP all you need is Miami. Use MiamiInit (comes with Miami) to detect and creat a file you then import into miami to set up miami. This will work as long as your provider does not use PPOE tunneling, DHCP with PPOE is only supported by MiamDX.
The other option you have is to wait for Roadshow the stach that comes with OS4.0 there will be a 68xxx version released and it will be the most complete stack released for the Amiga. The problem is it could be 2wks to 6mnths before it comes out.
So basically with Miami you need to find out if your ISP useses DHCP (Miami3.1g) or DHCP/PPOE(MiamiDX).