Ok, I'll be the guy to go against the flow.
This is the worst time in history to buy an SLR. Well, it really depends on your needs. That's how any response to your question should begin, in my opinion. I'll come back to that in a second.
If you go back 5 or 6 years and look at the state of digital SLR's and do the same vs. other mirrorless cameras, the disparity in output quality was pretty enormous. Look at this today and it's not so. How did that shift come about? From an industry perspective...
1. More interest in putting SLR sized sensors into compact camera bodies.
2. More interest in development of new series of lenses for digital-only bodies with smaller sensors (APS-C, 4/3, and smaller formats)
3. More interest in improving small sensor capability.
If SLR's still rule one thing, it's autofocus. Mostly, mid and high end bodies, but even some entry level bodies will be faster and more accurate to lock focus than other compact cameras. At the upper end there are all kinds of advanced focus tracking features. If you're shooting sports, birds, or weddings professionally then you probably do need an SLR. For example, an honest report from a non-pro who has shot several weddings.
One other aspect of the SLR is their optical view finder. Many of the compact bodies now offer electronic view finders, which are not quite the same experience, but still provide a familiar way of shooting. I prefer the far-left placement of the viewfinder on Sony and Fuji cameras to Olympus, but the OM-D is more true to an SLR design.
I think one perceived benefit of an SLR is access to a wide selection of lenses, especially with a full frame SLR. For some people this might actually be true, but for most of us, how many lenses do we actually own? As a full frame SLR shooter for many years I subscribed to this, even though I purchased almost every lens I ever needed within the first year or two.
Still, it's nice to know, when buying into a system the options to expand will be there. Most of the compact interchangeable lens cameras now have good lens lineups (all of which are continually growing). If we get out of the mindset "but there are only 12 lenses, and X offers 50 lenses" then we can start to scrutinize whether a system meets our actual needs or not.
As a full frame SLR user for many years, it's taken me that long to wrap my head around a new way of thinking. Only just recently did I decide to sell my SLR and use only my NEX 5N exclusively. I arrived at this after considering a few key points:
1. FF offers better high ISO (color accuracy and noise) performance - Modern APS-C is good enough, it's amazing how far sensor tech has come. I will "cope"!
2. FF offers more lens selection - Doesn't matter. I will be using a 10-18 zoom, 24/1.8 as my primary lenses, an occasionally a couple of older small and light manual focus lenses.
3. FF offers thinner depth of field when all else is equal - I can get plenty of subject isolation on a crop sensor with a fast lens. I actually prefer the slightly deeper DOF most of the time.
4. My SLR viewfinder - I've learned how to frame and compose shots on the LCD of my NEX. I equate this to learning UL techniques to lighten up backpacking gear, it's a new skill for a different experience.
5. My SLR has an ergonomic body - Not sure why I chanted the mantra "it's easy to hold" so insistently. It's big, it's heavy, it's not something I want to backpack with, and it's not something I tend to take with me whenever I head out the door. The latter is important, I've been much more likely to have my NEX with me, and thus I've taken a lot more photos with it than I ever expected. Some I would not have captured otherwise. This was the initial eye-opener for me.
I'd put the image quality of my little 5N up against the Canon 5D mark II, and where the mark II is ahead, it's not leaps ahead. For me the upside is worth the tradeoff. There are a handful of mirrorless interchangeable lens cameras in this class now. Lots of really exciting things going on in the world outside of SLR's... too many to discount.