For the record: easyjet started in nov '95 with 1 200 series on wet lease from GB, operated under Air Foyle's AOC. Within a week or 2 they had doubled the fleet to 2 200's. Around about 1 year later they bought their first 300 second hand from Monarch. They continued under Air Foyle for a while until going it alone, if memory serves me correctly, once they had returned the 200's.
The 300 or any other higher series (4,5,6,7,8) has to be the machine of choice for a start up. No noise problems as associated with the 200. The 737 in my book wins hands down over the A320 or 146. The 737 is self sufficient at any airport, it has it's own stairs and an APU. It's a fairly compact reliable machine that can be quickly turned around with a minimum of fuss.