Charts and maps
I am of an age that prefers paper to screens — what if the boat electrics earth falls off and all the instruments suddenly stop working, which did once happen to me? Or the battery in your hand-held GPS is flat? One has to have some sort of paper although I can detect deterioration in my own traditional navigational skills as I rely more and more on the chartplotter. However, I confess that because they are so much more convenient than rolls and rolls of paper, I do frequently consult the Navionics charts on my computer at home, for winter dreaming and planning. And on my iphone when I’m sailing. Of course, paper is so much nicer to handle both at the chart table and in the cockpit, but it's expensive — at least the Admiralty charts that I have bought over the years were. But you don't these days have to have a huge collection of standard charts of the sort used on battleships, but rather the small craft charts for the main cruising areas around the UK — Folio SC5611 ‘West Coast of Scotland: Mull of Kintyre to Point of Ardnamurchan’, which covers almost all the anchorages on this website, plus Folio SC5616 ‘West Coast of Scotland: the Point of Ardnamurchan to Shiant Islands’ which covers the rest. I am not an Imray Charts person for no very good reason other than I started off with Admiralty charts and, like my bank, haven't changed my habits. (At least not until I left RBS in disgust and moved to the Co-op following the financial crisis in 2009, and then again when the Co-op came under a cloud, to the only mutually-owned building society in the UK, the Nationwide.)
You should also buy (at very modest cost) the Antares Charts, unofficial but brilliant very large scale electronic charts and related pilotage information. They were created Bob Bradfield, a retired investment banker, who has been cruising round the West Coast for years, these days on a motorboat called 'Otter' (even though I think he lives in Essex). And he is constantly extending and updating them. I don't approve of the honours system except for MBEs, and Bob has one of those for his hydrographic efforts — so very well deserved. His has produced charts of places which may have not been surveyed for years, particularly many of the more interesting and intricate anchorages. Highly recommended.
As for maps, you can't do better than the Ordnance Survey maps of the area — brilliant. I have included a link to the on-line Bing maps on the home page.