For my company, the following requires the specification of an alternate

1st Alternate:
123 Rule
Landing Performance
Offline Charter
No Instrument Approach Procedure
Driftdown
Mountainous Airports w/high MDAs (Optional)
PIC Discretion (x-wind at or beyond limits, etc)
Takeoff Alternate (departure wx below landing mins)

2nd Alternate:
Marginal (within 100+1/2 of actual + derived minimums) weather at Destination AND 1st Alternate
Use of Exemption 3585 (relief from conditional remarks in TAF, i.e, "TEMPO")