Re: lee aniversary kit
I have a very similar set, I pieced mine together as I went along. I too did eventually move from the the Lee dies to RCBS, as I feel they are of better quality and are a bit easier to adjust.
I would not "replace" anything from the kit, but here are some additional items I would consider.
Loading manual of your choice, Lee, Speer, Hodgdons etc. The annual Hodgdons is sold at Wallgreens on the magazine shelf in CO.
Digital scale: The Lee scale is very accurate, and easy to use for working up loads. I use a simple Frankford Arsenal scale to measure the throws from my powder measure, quick and easy.
Powder trikler: Trying to increase the load by 1gn or less at a time can be frustrating
Redding Imperial sizing die wax: No dented brass, you put it on like carmex, dab your finger and rub it on. A qtip to do the inside of of bottle neck.
Inertia bullet puller: Seated that bullet too deep? Wanna change some surplus rounds to hunting? Gonna need a puller. RCBS makes a collet puller, but a $5 inertia puller and a 2x4 and you are golden. Kinda freaky when you first do one though, nothing like banging a live round against a wood block to get you squimish.
Loading tray: You have to put them cases full of powder somewhere.
Lee case trimmer: If you will only be doing one or two calibers then the lees are great, you can chock them in a drill as well. If you can afford it, a lyman or equiv trimmer will make life easier.
Of course one of the most important is a good set of calipers, digital are cool, but I find I have to constantly recheck zero as they can flake out, but not too bad.
For the future:
Brass tumbler: Extend the life of your dies, shiny brass, no more black fingers. Makes cleaning up brass less of a chore.
I still have my starter set, and eventually want to move up to a turret style press. The reason is 223, I shoot a bolt action and can easily to through 200 rounds in one sitting. I am sure if you have an AR it will be much more. 223 can challange you patients on a single stage press. I just do 100 at a time and move on till later.
Have fun and be safe, if in doubt, throw it out.