Here's a short form review of the Ultramarines upgrade sprue which has some really awesome bits for your 30k Marines.
I've included photos of two helmets, a chest plate and a gladius (short sword).
I don't always bother removing the icons (e.g., Ultramarines) as you can mask them when painting your converted models and this helps save time.
Pro Tip
Don't use resin swords and axes as they will invariably bend which can be fixed but is a pain. I only use plastic power weapons now... Makes your gaming life a lot easier !