Hi Chris,
Congrates on the xmas present, I hope you know where it's hidden and can play when everyone goes out
Can you let us know what camera you have got and what lens as this will aid in the suggestions given.
I would say for landscapes a tripod is a must, I was on a budget and brought a £40 one for commet of all places thats great for my needs. Also depending on what lens you have you may want a wide angle but this will probably be down the line.
Depends on your actions shoots are they in/out doors during the day etc. as this may effect a whether a flash is needed or a nice fast lens (prices can be expensive)
Bags are a good by and spend some time getting the right one as these seemed the thing people change the most.
Memory Cards and some filters (c.Poloriser for the landscapes) 7 day shop for good prices.
I am sure there are other things I have forgot but let us know what kit your getting to help.