That's one of those things where money can go a long way quickly - fat i/o (including network if you're off-loading, sharding, peering, vdbs etc.), good cpu, efficient log sizes. Sticking to the basics is probably the best - if you're running high transaction and data change rates then the collective throughput "off" of your transaction server(s) is every bit as important as the throughput "on" the server(s).