So I was poking through Facebook (bad habit I know, but hey, this time it was useful) and I had cause to be glad for the new formatting when I had a link to a blog posted on my page. It looked interesting so I followed it to Rachelle Gardner's blog ( http://networkedblogs.com/nwlT3 ). She's a literary agent and has some really good articles on her site that speak on a wide variety of subjects in regards to writing. There was also a link to another site for a blog by Colleen Lindsay ( http://theswivet.blogspot.com/ ) that had a very interesting article regarding word count for novels of varying genres. ( http://theswivet.blogspot.com/2008/03/on-word-counts-and-novel-length.html )
Generally, the word count suggested for most novels (excepting YA and younger novels which are generally shorter) is between 90,000 and 120,000. It's pointed out particularly in the comments that there's also been a lot of novels published that must be over that count. (Patrick Rothfus's The Name of the Wind or the majority of Adrian Tchaikovsky's Shadows of the Apt series for example are both extremely long and detailed.) There was a lot of arguing back and forth and if you want to take it very seriously, honestly these women are or were Literary Agents and there's a reason they link to each other and say what they say. If you want to get published, especially the first time they say you must be aware that the general word count for novels is somewhere between 90,000 and 120,000. Having said that, and having read the much longer books that have been printed by newer authors (and being someone who reads exceedingly quickly so enjoys longer books) I posted a comment with a theory (that will appear when and if Colleen deems it worthy) that I think bears repeating here.
I believe that the people with experience are right and that the general word count for most novels is going to be within the aforementioned word counts. However! I also believe there are two things that will forgive almost any page count. Spectacular writing and sales. If you have well over 120,000 words, you are asking your reader to sit and stay with your book for hours on end and even if the reader is an incredibly fast read, it better be a d*** good book. A longer word count gives you more chances to wander, more chances to mess up and more chances to lose your reader so that they never come back. While it can also allow you more time to develop your characters, plots, sub-plots and everything else you might need in your book if you do not do this in a way that can hold someone's interest through every sentence of the book then you need to cut it down. If you're losing the reader, especially more than once, you've already lost the agent.
If you don't need the scene then it shouldn't be in there. It can be for character development, it can be for plot development it can be for whatever you want but it should advance the story or it better keep me very interested and I say that as a reader, not so much as a writer. If you can't keep my interest I won't finish your book and I won't buy your next one. Assuming you get a second chance. If your book doesn't sell well because I don't finish it, I also won't recommend it. That means your sales are already below what they should be. Your agent/editor is going to be the first person to read your book and whether it's 30,000 or 200,000+ words your first priority should always be a story with purpose.
Keep in mind though, you can have a scene that advances the plot without it being full of action every second. There are ways of keeping interest that don't need to be a fight or really active and make your reader want to turn that page until there are no pages left!