g scale indoors and outdoors
some items to address the above questions:
1) starter set power supplies are made to run the train in the box only, don't expect them to power a two-motor engine (like a six axle diesel).
but, it doesn't mean you must shell out hundreds every year to get the bigger engines to run well. one purchase of a quality pack could serve you for years perhaps decades.
lgb, piko, aristo, mrc all make some good units.
lgb's controllers are excellent like the 51070 (street $150).
piko now has a similar item too. these throttles need a power supply but you can use DC or AC fixed-output transformers like the brilliant Mean Well switching power series @ 6+ amps for under $50USF. once set up, you don't have to worry about running lgb sound equipped with these. very expandable as your needs grow too. see
www.reynaulds.com
aristo's large power supply has 10 amps or more and you can use the train engineer system for radio controlled wireless, you can also use a low cost Mean Well unit with the Train Engineer.
mrc has the Power G pack (street $160) that will run one train out of the box , gives you 10 amps at 22 volts, and you can "add throttles" to it (like the LGB 51070 or Aristo TE) as your pocket book and train sets grow...
yes, there are lots of track systems now. i stick with Lehmann/Marklin. i prefer the system outline and turnouts from LGB. also, you can get used LGB off ebay for really good prices and used LGB track works like new.