Just passing by - since it's hard to add something worthy after previous comment. But I'd like to add that freshness of beans really matters a lot. I read once that oils start degrading right after the roasting, that's why the fresher the roast the better. That's not a gospel truth, though, and some coffee makers like to experiment older beans (up to 1/2 of a year). Thanks to weinoo for pointing it out.
Don't forget that you'll need a proper storage for your beans as well. Vacuum sealed dark glass jar would be perfect - just don't left it under the sun.
And another tip from a coffee enthusiast, try to document each step you made before you got a good cup of espresso. Bean type, origin, size of grounds, which water you used... That will help you to reproduce the whole process since, it's a chemistry after all.
I love to mix Colombian with Guatemalan. My equipment is not the best, but it works fine for me.
upd: and as a result I totally forgot to mention it! Breville BS810 for espresso machine and Baratza grinder.