Mouser and Digikey for opamps.
Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".
Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).
Some ebay sellers tend to sell fakes, especially where OPA627 and AD797 are concerned, or they sell opamps taken from very old, heavily-used equipment and call them "new".
Some more noteworthy chips: AD4898, AD8597, ADA4627-1B, OPA209, OPA1611, OPA602B, OPA1652, OPA1641, LME49860, and AD8610 (this last one is generally best in portable devices as it cannot take the voltage of full-sized equipment, generally).