current source with op-amp+NMOS
It would be better if R23 was about 170\$\Omega\$ (1000||220 -10) to balance both the low bias currents and the effect of impulses coming out of the inputs. 

As in the comments, the R15/C11 affect the phase margin. If you feed your current source a step input and it overshoots or oscillates then you may wish to add C11 to control that. C11 is probably necessary unless the MOSFET is a very small one, as that op-amp gets twitchy with very little capacitive loading. I think R15 would be better in series with C11, but it's usually not necessary unless you're really interested in fast response times.