I've said it several times:
• I spent over a month designing the original army list
• You always make an immediate change after your first game to adjust
• Ultramarines with Space Wolf allies is one of the best combinations
Drop Pod Space Marine (DPSM) armies are inherently aggressive and are one of the best alpha strike armies. By designing your army list to be MSU (many small units) you can have both an alpha strike and a beta strike. Most armies cannot hide from DPSM... The first turn can be brutal. Most players now have zero or very limited experience versus DPSM as they went out of vogue over two editions ago. Some have said it's a glass hammer but that's not true if you design a fundamentally sound list. Proper placement of objectives allows you to take quickly take control of the dominant area on the table.
I think Space Marines are entering a new golden age with a wide variety of viable builds. The cost points wise for most Space Marine units dropped drastically and overall are better compared to the previous edition. Let's take a look at some of the other potent combinations. Some players believe that a pure Space Wolf army is the strongest build but I think they have some inherent limits since their codex is out of date now. Space Wolves are definitely one of the top allied choices with the Rune Priest and Grey Hunters. The Rune Priest obviously brings a lot to the table with his anti psychic ability (rune staff) and amazing psychic powers (Jaws of the World Wolf and Living Lightning). I used to really hate on JotWW but with the proliferation of monstrous creatures (Riptides, Wraith Knights, Daemon Princes and to a lesser extent Greater Daemons) this psychic power is almost mandatory.
Two other Chapters viable for DPSM are as follows:
• Crimson Fists (Pedro Kantor makes Sternguard scoring plus Bolter Drill)
• Salamanders (they also can buff Sternguard with twin linked combi-meltas)
So these are your main go to Chapters. Another viable Chapter are White Scars with their amazing biker units but this is not a pure DPSM army and I've actually discussed this hybrid build when the codex was first released.