/NIN, /SAM, and probably /DNC for good measure.
/NIN is good for Utsu, or if you want to dual wield for some reason.
Why would I need /nin? I'm using a Great Axe and since I'm not tanking I see no need to have Blink.
Because if you're doing good damage, you will
be tanking at least part of the time. Whether or not /NIN is justified tends to come down to whether you expect to be tanking for extended periods of time, and/or against things that Third Eye won't block, such as magic.
Depending on the party setup, you may be expected to 'voke and split tanking with another DD/etc. XP parties, and certainly merit parties, don't have a "tank". Many other activities will use DD/NIN's as tanks (Nyzul, Salvage, many Limbus runs, some Dynamis zones, etc).
/SAM offers some great offensive gains, and still offers Seigan/Third Eye for those oh shi- moments (though you won't get Seigan from /SAM until 70). Generally speaking, this is your subjob to maximize damage output with a 2h weapon for higher levels. The only real question becomes whether or not it's manageable for your party setup/event. Seigan/TE is not as reliable as Utsu, there's only one timer, and there are different tradeoffs...TE won't absorb magic, but it will count multi-hit moves as one block, etc.
/DNC is your best pick for solo, or possibly low manning something. Again, basically no offensive bonus (well, you get some enfeebles n' ACC bonus), but rather than avoid damage, you can use TP to get HP back. For lower end stuff, this can keep you alive, at the cost of WS rate.
/THF technically still could have a use, but not usually.