use a picaxe with a dallas digital temp IC, the IC are say $5-$10, and on paper within 0.2deg C, long leads are not such a issue as the Anolog to Digital is done in the chip and the pic axe can talk to it with the "get temp" command
The pic axe (the smallest chip 08M is say $5 - cheap controler) or move to 18X where you have a heap more code space etc
you can get a datalogger and the LCD "kit" thats basicly plug and play although you get up in price a bit more
Programing is in "Basic" format and shouldn't take long to master
microzed in syd? sell all of this
www.microzed.com.au
www.picaxe.co.uk
note: these are not of the shelf solutions but component level, and or kits
Ben
P.S not sure how many digital inputs there are (different on each chip) but you can add aditional LM35, Lm34, Lm335 etc on a anolog input and use a output for things like turning heat on or off, pumps etc
and as normal power kill blah blah exp with beer and liquid so dont play with mains voltages....... esp when pissed
