Summary: 'Rated' miles is not what you will get, my experience suggests you will need a factor to reduce it by and that will depend on YOU. My factor for traveling to/from work is about .78 - so on a full tank of 225 miles, I'll get about 175 miles. A representative day for me, where I sit in the car for 2 hours making calls (and charging the phone) in addition to driving a total of 72 miles with heater, music and running lights, the factor moved to .57 ... you will definitely want to understand how you will use the car during a heavy day and size to that (or operate lighter on a 'heavy' day). Quick update on 2/19/13, drove 34.7 miles, consumed 56 miles of range, heater on 68 with temperature around 11 degrees outside, speed of traffic 65-70 for 25-30 miles -> factor of .62
The stated range by Tesla and 'validated' by a car magazine or two is 300 miles for the 85 kWh battery.
The EPA has required Tesla to sticker the car at 265 miles. Originally, after charging my Tesla in Standard Mode (versus Maximum) the stated range was 241 miles per the graphic above and now with the latest software the car is charging to around 225 miles. Full charges seem to get anywhere from 220 to 230. I let the car sit (unplugged) for 12 hours at 50 degrees and it lost 10 miles of charge. With software release 5.0, there is an option to reduce energy consumption while not in use. Using this option results in the car taking a couple of seconds to 'wake up' when you get in after 'conservation mode' has kicked in. Connecting via the iPhone (or Droid app) will take a good minute if the car is in conservation mode - I prefer not to use the conversation mode as I use the app all the time to cool or heat the cabin before I get in. On a cold morning (26 degrees), I drove the car 26.5 miles and the stated range went down by 34 miles. The trip took 40 minutes with 15 miles of expressway driving (speed of traffic around 70), 6 miles of 4 lane cement divided road with a stop every mile (speed around 50 from stop to stop). This is a very representative day to work and limited 'enjoyment' of the 'performance package' on the car. The entire scenario involves the same trip to work, a drive to lunch, and then sitting in the car 2 separate hours for conference calls - which is a perfect use of the car (for me) as it is quiet, comfortable, and climate controlled without running an engine.
I've had the car to the local 'track' and while it is very heavy at ~4,700 lbs, it is very quick and feels quite stable at 90 mph - to the point where you don't realize the rate of speed that you are traveling. Where conventional cars get louder the faster you go, here, the sound of rushing wind picks up a bit and that's it. As one might imagine, the 'miles remaining' number takes a severe beating traveling at that rate for a period of time and you wouldn't want to plan a 225 mile trip going 90 mph. The regenerative breaking is excellent at slowing you down without hitting the brakes and it comes on a bit 'gradually' from a high rate of speed; e.g., no nosedive when you take your foot off of the gas. The regen feature activates the brake lights at a certain point so those behind you know you are slowing down - the 'Charging' screen on the main console actually shows in realtime the status of the car; e.g., headlights, brakelights, doors open, etc. In cold weather, the regen feature takes a while to 'warm up' before it will actually start regening or how agressive regeneration is.