The River Rock light that I purchased at Target is a single AA cell light. It was advertised as 1 watt, and I believe they use Luxeon LEDs.
If your light is the one that looks sort of like the small single AA Fenix lights with a pocket clip, I have one. I thought it was quite nice until I got my Jetbeam C-LE, which has twice the output (with the same runtime), or twice the runtime (with the same output), and a much better beam pattern. The C-LE also has even lower power modes with longer run times (up to about 30 hours), plus a scratch resistant glass lens, and great looking HAIII finish.
The C-LE is basically twice the performance in every category for the same 20 bucks I paid for my River Rock 1W 1 AA.
The Jetbeam is certainly not the only bet, the Fenix lights also offer top notch name brand build quality, and contrary to what has been said here, they are not really that much more expensive then the Target Department store lights, if you compare apples to apples.
With Fenix you can get a slightly better light than your River Rock for almost the same money, or two or three times the performance and features for proportionally more money, but the key thing to remember that Fenix is not really charging you much of a premium over what you are paying for 'department store' grade lights at target or Wal-Mart when you compare similar lights.
Check out the Fenix Civictor V1 light -
https://www.fenix-store.com/product...id=76&osCsid=132299e3814047b1b1aeb779af6538f9
There is a Fenix-Store 8% CPF discount [order with code CPF8] so this light ends up costing less that 25 bucks [shipped] which is in the same ball park as the River Rock, but the Fenix has a nicer beam pattern longer run time and scratch resistant glass lens.
Sure you can spend two or three times the money if you want to get a Fenix light with proportionately more output and features, but even if you NEVER expect to need anything more than a simple 1 AA x 1 mode light, Fenix would still be a better bet in my opinion due to the glass lens and better overall performance. Of course, if you drop your flashlights several feet onto hard concrete a lot, or tend to loose them a lot, then cheap disposable department store lights are probably your best bet, despite the lower performance.