yes. you should plan on providing food for the vendors. depending on the venue and organization you've hired, they may have different standards for this. be sure to ask so you have all the info.
if you prefer vendors not eat with your guests (and don't feel guilty about this choice, you may have an obligation to feed them, but they are workers, not guests, afterall. )make sure you set aside a decent room for them and that the caterers know to put however many meals and drinks they'll need into that room. also make sure they have a place to sit and a table to eat at. don' make alcoholic beverages availableto them, as they are on the job and not there to party. if you are having a band, speak to them about when they will be wanting to take a meal break and make sure the food is there for them when they break. other (non-performing) vendors won't be as time constrained, so can eat whenever the food is served to guests.
when i worked as an event coordinator we would send vendors' meals to the band's green room (you should plan on having a green rom if you are having a live band), and all vendors would eat in there. we were always careful to respectfully provide enough food and drink for all of them.
I'm a photographer and our clients usually provide a meal. Have the photographer's meal served immediately after yours, before the other guests get theirs even! That way they will be free again when the speeches etc. start towards the end of dinner. Guests don't want their pictures taken while they're eating so this is a good time to feed the photographers. Also, don't put your photographer in a separate room away from everyone else. By the time dinner is served they will have interacted in some way with most of your guests and are generally not viewed as "workers". In fact, we've regularly had guests at the wedding ask us why we're not sitting with everyone else if we have been separated.
The main reason you don't want your photographer in a separate room is that they will not be on hand should something exciting and unexpected happen. We don't take a strict half an hour and disappear until it's over. We stay close and jump up to capture those moments I just mentioned. After all, that's why you have a photographer! We can then return to our meal when things die down again.
I am also a photographer and I completely agree with everything Paul just said. I highly encourage couples to seat me in the heart of the action for our meal so I don't miss a single moment. The added bonus is the more relaxed photos we get when guests feel like a photographer is part of the family instead of a worker.