Personally, I'd recommend an 8 weight rod for an "all around" salmon rod. This will give you enough backbone with springs and chum, and be light enough to enjoy the smaller pinks and coho. Also, as discussed on other posts - not all rods are equal. My Sage 896 RPL+ has the lifting power of a 9 weight rod - easy! Also, I'd recommend a fast action rod since you'll likely be tossing sink tips. As for xgolfman's comments - I'm not going to argue with his 9 wt recommendation as he makes excellent points. If you end up foul hooking a large fish such as a chum, don't bother playing the fish out. Just point the rod tip at the fish and break off. Trying to horse in a foul hooked fish like a chum or spring will risk breaking the rod - even if it's a 9 weight.
One thing - and this has been repeated many times on this forum. Go to a fly shop, speak to the staff, and try out rods and see for yourself what you like. There are many decent rods that are reasonably priced. Good luck and have fun!