sticky thermostat

i was on my way to work and car over heated(240+ and still rising), i pulled off so i could check the hose from the stat housing and was cool so i knew the stat had stuck. so i waited around 10-15 min to let it cool down enough to atleast get me past the road construction area and closer to somewhere i could get to a phone to call anyone, drove it from then on to work, and never got higher then around 180(thermostats temp i have in now). it drove home fine to. so could it have been a 1 time thing or should i go ahead and replace it again i replaced it in late spring early summer to the 180 from a 210 i think so it would run a little cooler in the cen. tx. heat, had put the 205-210 to get car warm enough in winter, the 180 doesnt heat up enough to warm the whole car for if i have anyone with me, so if i have to replace it was thinking of maybe a 195 to be in the middle. whats the difference in the different grades, economy, regular, premium, and the hi-pro & power performance, i know they all are in different brands, and heard of reverse poppet or whatever but didnt know about it. those listed range from $4-$13. thanx for any help on this, car seems to act up with the seasons, and around pay weeks too.

i dunno all of that stuff...i run the 170 with an adjustable temperature fan relay...and i have my temp switch to turn the fan on at 180 and i have no problems summer or winter...and i live in austin texas

some time mine sticks when i first start it up normally i just hit the top of the dash and it just flopps around back to normal but my cars an 85 so kinda getting a little old