The first GTX 260 and all GTX 280 were produced in 65nm, but they are not on the market anymore. ALL "GTX" GPUs in 65nm have that issue. There were slightly overclocked versions of 65nm GPUs, but in my eyes that was ridiculous.
The newer GTX 260, the GTX 275 and GTX 285 do NOT have the heat issue, even the overclocked ones. Never buy a used GTX 260, except you are sure that it is the 55nm version. But don´t rely 100% on that, there are reviews for almost every GTX card on the net. Read them before you buy a new card, there are always some black sheeps which have more or less serious problems.
There is also a speciality with these GTX 260 GPUS, there are some with 216 and some with 192 shader units, the 216 is the faster one of course. So if you want to buy a GTX 260 make sure its the 55nm version with 216 shader units. I don´t know if there are cards in 65nm and with 216 shader units but it´s better to take care of that and maybe ask twice than to buy old overheating crap. I´m saying that because I saw some german online shops which sell some old 65nm and don´t mention that in the description.