Wilton's are beautifully made, easy to find, reasonably priced. I have their largest set which comes with a very handy storage box, and then I've supplemented with additional tips for those I use the most (so that I can have several colors set up at once).
If you'd rather pick and choose, go to the Wilton site to find the charts that show the designs each tip can pipe. It's very helpful!
As for bags, ditto for Wilton for all the same reasons. I use 8" and 10" the most, and have a number of them. They clean well enough in good hot, soapy water to be used with royal icing afterward (which doesn't tolerate even a trace of grease. Just turn them inside out to wash them.)
Oh, also: I highly recommend you get several adaptors (don't remember exactly what they call it -- screw-on collar thingy) which allow you to change tips on the same bag without emptying the bag and re-loading the tip. (They have angled and straight and while I own both, I don't think I've ever used the angled.)
Edited to add that you can also buy the storage box alone and fill it with your own custom choice of tips. Do get the box -- helps protect the more delicate tips and makes finding what you want a ... piece of cake.