Excel is not that convenient for that, since the pictures can make it confusing in the long run (that would start at 4 trades, for me, since I can put many charts per trade). Plus Excel sometimes decides that your cell format is not what it thinks it should and rearranges it... painful.
I came accross something promising, Forex Control Center, alas the diary function is a mess, charts go from one trade to the other, comments of a trade erase those of others, some trades disappear... well, not reliable at all. Too bad, it looked like it had it all. So, I'm still looking to get rid of paper and scissors too..
I have used it for nearly one year. It is great. Support is great and directly from the developer. Is a tremendous time saver. I have over 1200 transactions in 2011 so far, and every one of them has been downloaded from Interactive Brokers with no input from me - it works flawlessly day by day.
Tags and filters allow you to review trades by individual securities, market sectors, etc.