Well, Bike captain or Chapter master on a bike with shield eternal is what everyone considers as a sorta default, now. Chapter master is purely better for 25, but Captain lets you have command squads, which can have bikes and an apothecary, so that's nice. However, I will also say that Honour guard are pretty awesome....most circumstances tough as a terminator, way more attacks. They really need to be in a LR, though. Which, y'know, I think is awesome, I love LRs and it's way fluffy for ironhands.
Clan Raukaan has that chains thing which is sorta complicated but for most purposes similar to the shield eternal.
You can do all sorts of different weapon options. Hammer, powerfist, relic blade, that burning blade thing, all good.
Nothing wrong with a master of the forge, either. Nothing wrong with any kind of Techmarine in a LR, thing could nearly last forever.
If they're not in a LR, I think you're cheating yourself if you don't put them on a bike, however. There's just pretty much no reason not to.