It is so important to use the best quality brushes and Roller Sleeves that your budget will allow . Good quality paints can look terrible when applied with poor quality tools . I would highly recommend quality brands such as Allpro , Corona or Wooster ( all made the USA )  – Yes Chinese imports are cheaper – but for a good reason ! For your walls I would recommend a 9″ Smooth  (3/8″ nap )  roller sleeve ideally from one the brands mentioned above . For cutting in around the timber work and ceiling I would use a 2″ synthetic bristle brush – these brushes are great for holding their shape making it easier to keep a straight line . For your timber work it will depend on what paint you are using – if its a solvent based product then make sure you use a pure bristle brush , if you are using an acrylic bases product then use a synthetic bristle brush . AllPro , Corona and Wooster have a full range of Brushes and Rollers to suit every ones budget.