After lots of reading from this thread I've purchased the F5500. It was a solid set with great PQ...settings were nice right out of the box but looked better after the firmware update and a bit of tweaking. Since it was my first plasma, I thought that buzzing noise plasmas made was a defect in the TV so i returned it after 2 days and got a Panasonic S60 (which made the same noise). The S60 required a lot more tweaking right out of the box to look good.
Both sets costed me the EXACT same amount (899 CAD + tax at FutureShop). Now for the comparison. I honestly think the Samsung was a better TV. The S60 had deeper blacks but I feel like the PQ on the Samsung was a tiny bit better (although this opinion seems to vary between people), it had 3d, better smart features, better speakers and is an inch bigger. For 2 Tv's that costed the same I think Samsung had more to offer. I miss my Samsung right now and might go back an get it if more calibrations dont get my Panny set looking better.
Btw I dont think you can compare the ST60 to the F5500...I think the S60 would be the better comparison. I saw the ST60 in store and it was definitely better then both sets I've owned