Thanks for the replies all.
Danadak: I don't have such exact specs, and I feel like really doing a thorrough analysis would take too much time in view of the scope of m project. I was just hoping to get some suggstions in terms of circuit techniques or maybe part families to keep in mind to get good performance, without full characterizing this (this is just one part of a large system we have to design, and we have only about 40 hours (on paper) left to work on it).
evb149: I made the assumption that since my signals are very low lever, and te idle consumption of the amplifier will be quite high, it will not change temperature significantly. On op of that, also see the above in terms of how I can't really do a thorough analysis.
Temperature measurement would make it too complex I think, and we are already hitting the limit of the what the arduino we are using is capable of (we are sampleing at 1MS/second with a 10bit ADC, and just getting that much data loaded into the arduino is a pain)...