I would get either HG/SS or RR. HG/SS has quite a few useful trainers and Energies (DCE, Pokemon Collector, Pokemon Communication, Pokegear, Copycat) as well as useful attackers like Jumpluff and Donphan Prime. It also has useful techs like Blissey Prime, Feraliagr Prime and Noctowl. The box ratios are also high, so you will have a lot of Primes and Legends you csn trade for cards you need.
RR also has a few notable trainers (SP Radar, Bebe's Search, Volkner's Philosophy) but it also has some of the best cardsin the format. If you get either Flygon Lv.x or Luxray GL Lv.x, you can either use them or trade them for something. It also has Nidoqueen and Raichu GL, which are pretty useful.
So I would pick HG/SS if you're looking for staples, and RR if you're looking for attackers.