I didn't realise that the basic Elster meters automatically push out data through the IR port. This is very useful for this kind of project! I dont think the Landis & Gyr/Ampy meters do this.
Reading the meter register is obviously a better way of monitoring the meter's consumption. Logging pulses is prone to missing a pulse and you need to log a base meter reading you want to track the total meter reading.
Some meters have an M-Bus interface. Its often used for connecting to energy management systems (or BMS). Its very common on a lot of newer meters and certainly most three phase digital meters. Heres an overview. http://www.m-bus.com/info/mbuse.php. It doubt this is any more difficult to interface with.