There's a bit of stuff at the front of one of the RHS Gardening dictionaries - either the Plants one, (the one which divides plants into types, subdivided by size, colour, and season of flowering), or the Gardening one. Have a look at both in your local library or a good bookshop and see if they give you what you want. And before you wince at the price, compare it with the cost of a couple of shrubs ;-)

There's three stages of gardening:

1) buy plants which are vigorous and easy to grow. Clematis montana feels very attractive at this stage ;-) The garden is soon bursting with colour

2) Realise that things can't all be allowed to grow as large as they wish, and cut back things so that they all live happily together

3) Realise that 3) is not possible and start making the hard choices - which do I like best, the mock orange of the lilac?

If you plan for the final garden, of full grown plants, it will look bare for a few years. I think you just have to accept that what is right in the early years may not be right later, and be prepared to make a lot of changes as you go through. It's part of the fun of gardening. And, of course, your tastes will change. So - have an overall plan, but don't be too prescriptive about the details.