The general sentiment is to get patched to 1.5, but you might want to try 1.2 as well. If you don´t save and load very often it´s not that bad, in my opinion at least. It´s definitely the best option if you don´t want to dl the hundred-and-something MB of 1.3, which is a prerequisite for 1.5. As well, 1.2 will allow you using siege towers on every wall level and your cavalry can charge into the rear of phalanxes without getting slaughtered (search for "butt-spike" if you want details on that particular issue).