I think that a multi-channel chip is fine for low amperage applications, but heat dissipation becomes the problem as power increases. For higher (but still modest) amperage loads, I use a Darlington - the TIP120 will switch 60 Volts, TIP121 80V, and the '122 100V - all at 5 amps. Henrik's suggestion of MOSFETs is a more educated suggestion, but I don't do much with high voltage/ amperage and have had good results with the 120. Physically separating them from the rest of the circuit and adding a heat sink to the 220 package is both simple and effective - for me.