Effects? I rarely use 'em, but I keep a few around just in case. Personally, I'd rather hear the sound of the guitar rather than a wash of electronically-generated sounds. I certainly don't hate effects - I know players who make good creative use of them. But for me, FX just get in the way of what I want to say.
A guitar straight into a low-gain amp adds a bit of EQ and harmonic distortion. The EQ is static - you set the knobs and then play. The harmonic distortion follows the signal - with a good amp and good technique, this is under the control of the player.
Effects, to my ear, cover up a lot of the player's technique with their own sonic signature.
Modulation effects, for example, all have some kind of LFO that sweeps the effect at a fixed rate (unless you have something like a Uni-Vibe with the speed pedal). So no matter what you play, there's this sweep-up/sweep-down modulation happening that is at best accidentally connected to your playing.
Wah moves an EQ peak up and down the frequency spectrum by rocking on the pedal. Here you have a bit more control, but (IMO) good artistic uses of the wah are few and far between. The way most players use it, the sound of a wah is just a cliche.
Echo is a little better IMO because it has a natural counterpart. Short echoes give a sense of space, while longer echoes give you a chance to build odd rhythmic figures that you couldn't otherwise perform. Even longer echoes let you play around with call-and-response figures. But in the end, echo is still echo and you either have to build your sound around it or find places where it works and use it judiciously. (Which, BTW, is what the best FX mavens do with all of their tools.)
The "sonic wash" I referred to is that sense that you know the player's sound is coming mainly from a particular kind of pedal, and not from playing technique. That takes all the mystery out of listening to a player, because all you have to do is figure out what pedals they stepped on. A lot of players get lazy and let the FX do the talking - they'll play something completely unremarkable and depend upon the FX to add interest to their sound.
Also, particularly with the modulation effects, there's a certain predictability that comes with the territory - your ear knows that the next sweep is going to be an awful lot like the last one in terms of duration, intensity, etc. Maybe it doesn't bother other people, but I get bored listening to music where the effects are featured as prominently as the performer.
My main complaint with FX is that they get overused to the point where someone's signature sound is associated with the processing rather than the playing. To me it's just a lot more rewarding to get my tonal variations from the least possible processing. As a plus, I can change my sound from from one note or phrase to the next without doing a lot of programming and tap-dancing.