Thanks for the info, scubasteve! A few lights you might want to consider are the Surefire A2, the Streamlight TwinTask 2L, the Fenix L1T/L2T, and the Surefire 9AN.
As others have mentioned, the Surefire A2's an excellent choice. It's a bit beyond your desired price range, but it would fit your needs perfectly and last you a lifetime. They go for about $120-$140 used on CPF's "Sell" or "B/S/T" (Buy/Sell/Trade) forums. It's small, light, built like a tank, easy to operate with one hand, and has two different levels (and types) of light. The LEDs provide a nice even low-level flood for close-up work, and the incan beam lets you "reach out" and light up objects far away. It's truly one of my favorite lights, and it would be my top recommendation. Wish I had it back when I was an EMT!
An alternative - often called the "poor man's A2" - is the Streamlight TwinTask 2L. Like the A2, it has both incans and LEDs. The disadvantages are that it's bigger, dimmer, and not quite as elegant. For instance, the A2 lets you instantaneously and effortlessly switch between the LEDs and incan; with the TwinTask, you have to cycle through a few presses of the button. The Surefire is also brighter, which means you can illuminate objects further away. Still, this may be a good solution for you, since it's available for about $50.
For a less expensive light, you might consider the Fenix L2T (which you can also get in smaller form factors to use AA or CR123 batteries). Unfortunately, it lacks some of the "throw" of an incan, which might let you see things further away. However, it has two levels of light, and in the AA and CR123 form factor is *very* small. It's also easy to use one-handed.
Finally, I'd seriously consider the Surefire 9 AN. It's a rechargeable light, which will save you money if you plan to use it every night. It's also an incan, which gives you better color recognition. Finally, it has two levels of light - 20 lumens and 140 lumens - which lets you switch between battery convservation and raw power. Unfortunately, it's an expensive light - you're still probably looking at $150 used.
Again, you just can't go wrong with the A2. (I'm a serious fan of this light, as you might be able to tell!) Hope this helps!
- FITP