Jayson is right. Kenny is right, too.
I'm at 49 MPG on this tank. Best tank ever. It's probably a little bit me, a little bit the car breaking in, a little bit the weather. I want to get 50+ MPG without trying TOO hard myself. But I will (or not) by driving safely. Kenny gets fabulous MPG by essentially driving 53 MPH and driving as if he has no brakes (planning well and keeping his distance so as not to have to use them).

There is usually a considerable margin above recommended PSI before the tire becomes in danger of exploding, but I personally wouldn't push it much past the recommended limit. I've experienced 2 blowouts in my life, and it can be a harrowing experience. If not for a guard rail, my whole family would've died in the mountains of Virginia 35 years ago, when I was only 11 years old.

Premature tire wear alone (and quicker rattles on the car) will counter much of the money saved at the pump. Consider this hypothetical: getting 53 MPG instead of 50 MPG due to extremely high PSI, but the tires wear out at 50K miles, rather than 60K miles (all just guesses).
Gas Costs:
53 MPG = 5.66 cents per mile (@ $3 per gallon).
50 MPG = 6.00 cents per mile (@ $3 per gallon).

Tire Costs:
50K miles (due to higher PSI) * $280 (4 tires @ $70 per tire) = 0.56 cents per mile.
60K miles (due to regular PSI) * $280 (4 tires @ $70 per tire) = 0.467 cents per mile.

Combined Costs:
53 MPG/50K mile tires = 6.22 cents per mile = $3110.00 over 50K miles.
50 MPG/60K mile tires = 6.467 cents per mile = $3233.50 over 50K miles.

If the tires STILL last 60K miles at high PSI = $3063.50 over 50K miles.

For $125-$170 difference over 50K miles, I'd much rather have a less bumpy, potentially safer ride - albeit losing a little bit in bragging rights. This doesn't take into account the higher chance of needing an extra alignment due to a pothole with higher PSI, since the tire is less forgiving. And the slightly higher chance of nail-puncture damage with the higher PSI.
To me, it's pretty much a toss up, and if so, I'll take the more comfortable ride.
Now you WILL save about 57 gallons over that 50K miles, saving some pollution in emissions and in the production of that 57 gallons of extra gas. But you are consuming tires a little quicker, resulting in some extra pollution for their earlier manufacture.

 

tire pressure now at 44, sidewall max.
soc usually 4-5 bars thus far. rarely goes higher or lower.

 

You'll get better FE as you drive it. In my opinion, there's no reason to drive in a manner that annoys others or makes it less fun for you. The only hypermiling techniques that I do are, I will drive with the load on hills (as long as it's only a 3-4 mph difference...higher than that and I just press the gas and stay at speed...no need to peeve other drivers.), I usually coast once I see a light has turned red in front of me, and I increase my following distance on the highway so my speed fluctuations are much less severe than they used to be (but it's not like I leave 300 yards).

Just these, and learning the car, and the car breaking have had me go from 44.8 on my first tank to nearly 49 mpg average. 4 of my last 8 tanks have been over 50 mpg, and my last tank was 51.6mpg without a long trip (my best is 53.3, but that was nearly ALL highway). My current tank is around that 51mpg area as well, all mixed city/highway. I have my tires at 37psi cold...good compromise between comfort, safety, and FE.

Don't get caught up too much in all this stuff, you'll figure out good ways to get decent FE as you drive the car, don't push it, or concentrate only on FE, or you'll be dangerous.

 

tonight, i got 47.5mpg over 40mi by using a quick foot off/on throttle maneuver whenever the gauge dropped below 50mpg. using this technique in city traffic, i was able to go into ev mode very frequently. requires a lot more concentration, however.
ride is much quieter w/ tires at 44psi.

 

It DOES require more concentration, but soon enough you'll find yourself doing it almost automatically. It quickly becomes habit, especially when it is reinforced with good MPG you can actually SEE

 

my usual 2.4mile drive to and from the post office yielded very poor fe today, mid 30s. the only difference was i usually drive there with the windows down, but today they were closed, and the fan (no ac) was on high. is it normal for the fan being on full blast to affect fe that much?

 

Most any 2.4 mile drive will yield poor FE. The engine will be cold, and you won't get full efficiency. Most of the people here with poor FE drive very short trips all the time. A cold engine always gets worse milage, though the effect is more noticable in a hybrid because a 20% drop in our cars is 10mpg, while in a non efficient car, it might only be 4. Also, we have a digital readout to tell us what we get on those short, non-fuel efficient trips.

 

that's a good point because my engine is usually warm when i drive to the post office, but today i drove it stone cold.

 

had some great runs today:
16mi@45mpg, mostly fwy
12mi@60mpg, mostly fwy (best ever, so far)
3mi@42mpg, city
9mi@49mpg, mixed
2mi@54mpg, city
3mi@51mpg, city
=49.6mpg
i think the frequent, quick off/on-throttle technique is making a big difference. in the city, when i'm in ev mode and the ice kicks back in, i just pulse off/on and go right back into ev mode at about 23mph.
i'm putting all windows down in the city, and a/c on auto at 75 degrees on fwy, windows up.
slow, steady acceleration to no more than 2k rpm whenever possible seems to work best for me, fe-wise.
i draft whenever i can on fwy.
add: the same fwy transition that was so scary at 55psi last week went fine today at 44psi. car felt well planted.
baby had her first bath today. will apply sealant after next wash.

 

today:
17mi@43mpg
7mi@47mpg
13mi@58mpg
4mi@44mpg
6mi@47mpg
3mi@58mpg
=48.1mpg
everyday lately, its becoming easier to meet and exceed epa figures.