Re: Building a SMD inventory
Start with 0805 and build out from there. It's one of the most common sizes, and is easy to work wtih. When you get comfortable with that, you can move to 0603 and then to 0402 if you're feeling obsessive enough. ;-)
Component kits are a good way to pick up an initial inventory, then you can buy in quantity when you need to restock. My last refill of 0805 resistors from Mouser cost 70c per hundred, so I generally tack a few values onto orders for other parts.
I've found that it's good to have seven decades of E6 series values: 1.0, 1.5, 2.2, 3.3, 4.7, 6.8, with multipliers of 1 ohm to 1M for resistors, and 10pF to 10uF for capacitors. With that you can build just about any new circuit without having to order parts and wait. When you start to feel limited with those values, you can expand to the E12 series by adding the values 1.2, 1.8, 2.7, 3.9, 5.6, 8.2. I got those one decade at a time while I was building out my own inventory.
Along the way, you'll pick up special values as you need them.