i would go with a couple of SD towers and SoS. you can pick between titans and CoE's or mix em. don't use CF's. mixing CF's, titans and CoE's makes absolutely no sense.
The best war build before items came out for EBs was OS_Romeo's build for the All-Star Wars 2011 1 SoS 10 Lookout Fortresses 10 Titans Lair 28 Circle of Elements
With the Advent of the new EBs. which come with new attack pots, Mithril, Items... Now you'd be safer with: 10 Lookout Fortresses 1 SoS 10 Circle of Elements. 28 Titans Lair Get all 9 items so far in EBs (correct as of Apr 6, 2012), get all the new Attack and Spy Attack Pots. And you're in business.
And of course not forgetting to buy 100 new ally slots Increasing your BFA to 1b/1b/100m/100m n you'd be a little safer. Lol
There is no perfect attack build. The way this game changes (in the way people play) means you need to keep changing your build. At the moment I am loaded with cf. This is because most system wars that happen lately are fought from pin -due to the high number of hansel builds that there are. By having a load of cf I can successfully hit bigger players whilst staying dtw. If the style of system wars changes again - which no doubt it will - then I may consider changing my build again. Defensive towers and spy towers are not much use anymore. The two new attack/spy attack pots give an attack bonus of 72m. There is no defensive pot to counter these so only bfa can help. (these pots alone are enough to break through 7-8 towers). You would be better off having a building that gives you plunder. Pin is the only defence unless you have trillions in allies.
My thread on 'how to beat a player larger than yourself' gets stickied and unstickied about once a month. Do a google search for it and you can bump it. It tells you how to fight with any mixed attack build against any other player even of they're massively larger than you are. If you can attack them because they're within your 20% range you can beat them. Pretty simple.