Had to think about this one a bit so maybe I'll just leech off everyone else and comment on their suggestions
Keg: Haven't been there in a few years but personally I think it's a good suggestion if you want a steak and have a choice of a variety of cuts and options. It's a steak chain for the masses and it fills that need well IMO. Not sure if they serve prime grade or AAA grade though. I'm guessing a meal for two would end up being about $75-$90 tax and tip incl.
Just in case they extend it or you're in town by then, Morton's has a promo for two surf & turf meals for $109 per this thread
http://www.flyertalk.com/forum/showthread.php?t=555420 but it's ending May 31. Another option if you want a nice prime grade steak is Gotham Steakhouse [easily $150-$175 for two]. Not sure if I'd consider them family restaurants, though I'd guessing they'd be accomodating.
http://www.gothamsteakhouse.com/
Milestones: Haven't been to the downtown one in a few years but go for brunch (favourite dish is the prime rib hash) at a more local one every other month or so. It's another chain restaurant but they do a bit of menu development there so their food is kind of interesting. They have a couple of steaks (AAA grade I think) on their menu. I had a steak there a couple of years back and it was ok; nothing special. Yes, I've had the odd bad dish (artichoke appie dip was cold/frozen) but they'll make it up by not charging you for the dish (standard). [$50 for two?]
Cactus Club: Also on Robson Street. Usually has nice looking waitresses. Yes, that's the first thing out of my mouth. Another chain restaurant. Kind of a funkier Milestones but pretty much the same genre. [$45 for two?]
http://www.cactusclubcafe.com/
Red Robin: Definitely a family oriented chain but I'd somewhat equate it to TGI Friday's. [$30-$35 for two?]
Hon's: Tasty, cheap Chinese food. I wouldn't consider it a "standard" Chinese restaurant though. More of a cafeteria atmosphere (loud, big open floor plan, tables close to each other, etc) though they do serve you at the table. I usually order a plate of potstickers and a bowl of won ton noodles instead of regular dishes. [$20-$25 for two?]
Kirin (on Alberni): Excellent chinese food. A couple of my friends had their wedding reception at this location. I and other friends had our wedding receptions at different locations. It's kind of tough to get good variety when eating chinese for two but it's probably your best restaurant Chinese option in the downtown core. [$30-$40 for two?]
http://www.kirinrestaurant.com/
Whitespot: Another chain. I consider them pretty standard family dining. They're trying to be more sophisticated but I don't think they want to stray too far from the traditional homesy type food they serve. I only go to Whitespot every few months for breakfast/brunch. [$35 for two?]
There are a couple of Japanese "tapas" places on the Denman end of Robson: Guu with Garlic, Gyoza King, and Hapa Izakaya. Wouldn't really consider them family restaurants but it's kind of a different spin on what one would typically expect from a Japanese restaurant (ie sushi). [$50-$60 for two?]
Above the street level on Robson are a number of restaurants who's names elude me since I haven't been to them or haven't been to them in a while.
There are a lot of restaurants on Denman that are within walking distance. The wifey and I typically walk from Granville & Robson, down Robson to Denman, Denman to the beach and back for an evening walk every so often. There's a couple of gelato places on Denman that you can get dessert at after dinner.
http://www.mondogelato.com/
Probably at the limit to where you'd want to walk is Romano's Macaroni Grill. It's located a few blocks up from Davie after you reach the beach on Denman. The food is equivalent to Milestones IMO but the delivery to more fun (opera singing wait staff). [$45-$50 for two?]
http://www.macgrillbc.com/
If you want a "nice" hamburger, Vera's Burgershack and Fat Burger are also located at Denman. [$20-$25 for two?]
http://www.verasburgershack.com/ and
http://www.fatburger.net/home/
For lunch, you might want to try Caffe Artigiano on Pender if in the neighbourhood. I ate there while on a course downtown at the recommendation of friends. I wouldn't consider it a destination but the food (and coffee of course) is good.
http://www.caffeartigiano.com/index.html
Hamilton Street Grill - never been. Old Spaghetti Factory in Gastown? It'll be a bit of a walk but it's an ok place. Lots of other restaurants in Gastown but I haven't tried many there.
I think all the restaurants listed are "safe" bets because they've been around for a while. Depending on what you are looking for, some may or may not appeal to you. I don't think any of them will make you highly recommend them to friends that visit Vancouver though.