One of the very best gifts I've ever received was a fly tying kit. My father got me one about 13 years ago from Cabelas. It did not have the best materials, the tools were adequate and the vise got me through nearly 7 years of good tying before I finally WANTED to upgrade. The vise still holds a hook good enough but I wanted more from a vise.
Some of the materials I still use for certain things, and some of them did nothing more but frustrate me because I never found a good or easy way to use them. Mind you, I was doing this all from books that I found, this pre dates the wonderful resource that is youtube or other internet vidoes and SBS options available today. At the time, I was not in a position to take tying classes so my tying was self taught. What that kit did was get me hooked on tying. I replaced the materials for patterns I was working on as I needed them.
I do agree though, depending on what species of fish you're targeting, a kit might not be a good option, or in my case for trout, it was a very good option.
This whole topic parallels the first fly rod setup in my mind. Is it better to get a package deal, or is it better to buy ala carte and get better components? Honestly, I think both are very personal decisions that I'd recommend without hesitation as long as I heard the right things from a prospective buyer. In my mind, much of that is dependent on the type of I'd perceive the potential buyer to have. Nothing set in stone though, we can all change our minds, right?
If you're on the fence about fly fishing or tying, a kit might be a good way to go to put you in the game without much funds spent. This is also a good option if you're not in a position to spend lots of money on the pieces needed to get started. One downside that I see in either case is that if you go this route and don't stick with it, it might be harder to sell your package or kit.
If you are pretty sure you're going to stick with it, I'd be inclined to go ala carte provided that you have budget to do so. You can spend what you want, but it could very well be more expensive but you generally can get better gear and what you want. If you don't stick with it, it could be easier to sell if you get something other anglers are interested in, or not. All depends on the gear. You'll likely get better materials/equipment, but once again, some of the kits and starter packages get the job done just fine and may actually be the better deal. The kits/packages are ever changing so as another poster mentioned, this is one of the difficult aspects of going the kit/package route.
Its worth noting that sometimes a local fly shop can help put together a package that you don't see listed on a website, so it's always good to stop in or call and ask them. I've often said that a good relationship with your local shop if you have that luxury is worth its weight in gold. This is a great way to get that relationship headed in a good direction.
All of this said, I believe Ard made a comment about how the options today were much better than those he had back when he started. Although I didn't start quite as long ago as he did, the same is true even within the past 10 years. Ultimately the most important aspect in all of this is to get more people angling and embracing the fun of it!
Sorry for rambling, it's been one of those days @ work and this was a good way to separate myself from that, though I'm not sure how much sense all of it made