What's a good theme for a Space Marine Imperial Fists army?

Seige warfare, like vindicators and thunder cannons? Classical, like thunder hammers and power fists? Heavy weapons, like devastators and Sternguard? Or versatile, like the Ultramarines? What's a good theme for a Space Marine Imperial Fists army?
Okay, well the Imperial Fists do specialise in seige warfare, mainly things that break the lines like vindicators, vandurguards and thunderfire cannons. When it comes to special weapons they prefer to use thunder hammers so it would be pretty simple to have a few assualt termies in your army aswell.