Just have to add my .02!
Agree with all the nods to the personal trimmer (although I find I use that less and less now that I have the 12" one- I use that cut pictures and paper- it will cut the 12" paper).
The cutting system- I always use my circles, sometimes my ovals, rarely any other shapes.
Yes to the tape runner and I think their pens are high quality and last a long time.
Also love the square and circle (and star) punches. Rarely use my hexagon. I like the heart too, but not a must have.
I like their stickers, but only buy if you have a specific use in mind- like if you have a bunch of animal pictures, I think their zoo ones are awesome; same with the sealife park (like if you have a SeaWorld trip to scrap).
A snap pack is great- there is a new Disney one! It comes with pre-cut papers, stickers and an idea book of how to put together an entire album (usually 7x7 size) in a 'snap.'
Has anyone mentioned short-cuts? Love these- these are pre-cut papers in all sorts of colors, strips and sizes- makes album making super easy. I love CM albums- I used other albums for years, had one fall apart on me, and switched to CM. Pricey, but worth it. Their albums don't hold regular 12x12 paper because there is a strip of 'jeeping' on the edge of the pages to make the album sturdier. You can just trim off a 1/4" of an inch or so (a few mm) and your papers you already bought will fit just fine!
So, in short, I would definitely get:
the 12" trimmer
the circle and/or oval shapes with mat and blades
tape runner
1 pack of short cuts (depending on what colors you like better)
at least the black pen
And if you need an album, the 12x12 size is the most common and holds a nice amount of pictures. You can fit an additional 2 sets of page refills in each album (it comes with 15 pages, so you can fit 45 pages total in the album, give or take).
Hope this helps! I love CM!