Pick your favorite. My first army was Raven Guard because they're my favorite marine chapter. Their chapter tactics aren't the most competitive but I like them a lot. I bought the Dark Vengeance set and split it with a friend. He got the Dark Angels and I decided to make the Chaos marines Alpha Legion since their my favorite Chaos legion. It's all about what you like the most.
I agree with murtag. Just pick the one you like, its more fun. I started with BT but ended up making lots of Tau, despite liking them a lot, now I started again on BT because they are my favourites. You dont forget your first love . I assume you are an Imperial Fist fan, they have a nice supplement focusing on the 3rd company and captain lysander. He is a proper beast! And honestly Space Marines are easy to paint. Im a lazy painter so its cool for me.
No army is tough enough to not be picked by a newbie. People who call an army "the veteran's choice" find it only difficult because they have played some other army before. Good thing to remember when picking an army. And looking for strategies/tactics online is good for no matter what you pick.
I don't know, but a look in the Codex should clear that up. If there stands: "X Deat Company can replace their Meele Weapon for one of the following choices: ... -Thunderhammer Ypts" then you are good to go But if it says: "X Death Company can replace Bolter and Meele/ Boltpistol and Weapon for one of the following choices: ... -Thunderhammer Ypts" then you are screwed Regulary, only Terminators can weld Thunderhammers with one hand, but they usually take a Shield with them, so no shooting acion going on.
