I'm a lifetime fan of friction shifting. Friction shifters (as opposed to index shifters) are simple shifters with no indents to automatically 'find' the gear and put the derailer in the right spot. They have no clicks to put you in a certain gear - you can shift anywhere in the range of the derailer's sweep. There are several reasons this is good:
1) Less to tune up: when you change a gear cable with indexed shifting, there is a slight process to getting the derailer to land on the right gears when you shift. The cable tension needs to be just right. This is pretty easy if you've done it a hundred times, but most people haven't. Most people have index shifters, and when there is friction in the cable housing, or the derailer hanger is a little bent, they are powerless. The bicycle now rides noisily and "certain gears don't work." With a friction shifter, anyone can replace a cable and the setup is ridiculously simple. Remove the slack from the cable and tighten it. Done.
2) Compatibility freedom: Campy doesn't work with Shimano. Some SRAM works with Shimano, some SRAM needs SRAM. You need shifters with the right number of clicks to correspond with the number of gears. Basically, you need very specific and expensive stuff to ride your bicycle. With friction shifters you can have any number of gears from any company and you almost never have an issue. I've used Shimano 600 friction downtube shifters with a SRAM 4.0 derailer. Pretty stupid combo, but it worked fine and that's the point. This is especially useful when looking for super cheap parts to fix up your bicycle and keep it running perfectly for next to nothing. You get whatever's cheap with complete disregard for compatibility getting in the way. You still have to worry about some compatibility - but very much, and it's the easy stuff. Don't get a Campy cassette for your hub that needs a freewheel anyway. Then you're basically set.
3) Cheap: You can find friction shifters stupid cheap. Any bicycle shop can get friction thumb shifters for under $10 that you can put on any bicycle. They're made for straight bars, but they'll work on drop bars too with a longer bolt. Want some beautiful shifters? Shimano 600's looked hot, and those are still dumb-cheap. Want some friction shifter bling better than that? Rivendell has their "silver" shifters and there's a ton of ways to mount them. They can be: bar end shifters or downtube shifters - or you can mount them on Paul's thumbies or Kelly's takeoffs. Some of these nicer setups cost some bucks, but no matter how you set up your friction shifting setup, it's going to be worlds cheaper than the new 10spd STI or Ergopower nonsense. There's a place for that stuff, but to me it's nonsense. Like a $1000 ice cream sundae that everyone is eating because they don't know about the place that has homemade ice cream being sold right next to the cows that help make it. Personally, I don't see a problem with the super-cheap "Xundah" brand ones that you get from the J&B catalog. This catalog is carried by 99.9% of bicycle shops. You need to go through a shop to order something from it. Those are some cheap shifters, and they work great.
4) Reliable: the second your derailer hanger is slightly bent, or the second you get slight corrosion inside your cable housing - is the second that your bicycle will shift like crap. Not so with friction shifting. Friction shifting will put up with a lot more of this stuff - so if you're on a long tour, or just want to ride a bicycle without constant tweaking - go with friction.