I have just plain yellow/white/red av cables on my wii right now. I don't play it all that much unless I have friends over so I've never thought to upgrade. 
 
I was just wondering if the component cables really help the visual fidelity all that much or if I'm fine not spending the extra dough.

Yeah, they do. You might consider buying some cheaper component cables though, I got mine at monoprice.com I think.

With the Wii, it doesn't really matter, unless you plan to use the Netflix disc.

I have component cables on my Wii because I have an LCD tv and it looks extra crappy without them. I think they do make a difference, but it's not like you're moving up to 720p or 1080p or anything.

If you have a standard def TV they obviously won't help. It really won't be noticeable if you have an EDTV either (up to 480p.) If you have an HDTV, on the other hand, it makes the picture quality far less blurry to have your games running in 480p through the component cable, even if the resolution of the games isn't improved per se.

Component makes a difference over composite. If you've got the money to spend, spend it.

I say go get some. It definitely makes a difference, especially in terms of colour. Well, I think so anyway. At any rate, you'll definitely feel like it looks better :p

I think it makes a huge difference. Playing on an LCD screen, everything looks like garbage without proper cables. 2D stuff in particular are a lot clearer and sharper (text and menus, as well as 2D games, I guess). Some of the 3D games turn a bit jaggy when everything's sharper and you can tell the edges and stuff are probably meant to be blurred out on a CRT, but it's small price to pay. 

I'd say yes. Especially on bigger TVs. You lose tons of detail if you play on composite. 

Yea it can definitely help.  Makes things sharper, but the biggest difference to me is brighter colors.

When I bought my 42" plasma and plugged everything back in, I turned on the Wii (I still only had composite cables) and started playing Super Paper Mario. I immediately noticed the blotchy fuzziness (or was that fuzzy blotchiness?) that occurred when you moved or the screen scrolled. I immediately went and grabbed some cheap component cables for it and that fixed it straight away. So yeah, if you've got a nice big new telly, I'd advise you upgrade.

" With the Wii, it doesn't really matter, unless you plan to use the Netflix disc. "

You know, I have done this with both an SD and HDTV and I found a noticeable difference in the first case, and a HUGE difference in the second. I use the highest available input wherever possible, as it really does show. S-Video and Component are very close on an SDTV though, so that is an option as well.

Yes, it makes a noticeable difference, even on an SDTV. In particular it makes bright colors like red, yellow, and orange look a lot clearer than with composite.

Absolutely. Buy 'em. Seriously.

It depends on your TV to be honest.  Component cables means that the Wii will output in Progressive, that is, it will render a whole frame per second rather than two half frames within the same amount of time (AKA Interlaced).  If you have a modern TV, LCD or Plasma (or CRT if you're rich) then the Progressive output from the Wii will look substantially better in motion (specifically when panning horizontally) then it would when using Interlaced output.  Also, due the Component cables being split into three colours (or ranges really - Red, Green and Blue) there is more bandwidth (and more grounding) for each colour to be better transmitted along the cables, so colours should be brighter and clearer too.

 With the Wii, it doesn't really matter
If you have a standard def TV they obviously won't help.

done this with both an SD and HDTV and I found a noticeable difference in the first case, and a HUGE difference in the second. 

It definitely makes a difference.  If you have an EDTV then component cables will make you're Wii look really good.  SDTVs obviously can't use component cables, but through composite the WIi still looks good.  Wii just looks like shit straight up on an HDTV with the composite cables.  The component cables definitely help a lot, but still it doesn't look anywhere near as good as component cables with an EDTV.  Before people start going in on me I have a 55in Sony Bravia XBR4 and it's properly calibrated so it ain't the TV.  Also never buy cheap cables or third party cables.  There is a reason why they are cheap, they suck.  I bought some shitty VGA cables off of Amazon for like $7 and they were horrible everything was all blurry and had some kind of ghosting effect.  Just stick with first party.

I used to have a 50 in. 720p/1080i Sony. I played my Wii on it without component cables when I first got it. I later purchased the Nintendo brand cables and there was a marginal upgrade in the visual quality. I now have a 20 in. Sharp Aquos TV that is 720p/1080i. I am back to using the normal composite cables. I don't really see any difference in visual quality anymore. I really think that the difference between 540i/540p is nearly non-existant.  
 
If you are going to get them I would buy the cheap shit brand though. The difference definitely is not worth the Nintendo branded ones.

It makes a noticeable difference (I have about a 50 inch Vizio, supports 1080p), and is worth the money, but the Wii will only go up to 480p. It's not going to match the sharpness or beauty of 720p.

Yeah, about a month ago I got some for 4 bucks from Radioshack. 

Looks better, yeah. Don't get too close to the tv, though, it really brings out the jagged edges.

Similar question: Any particular brand?  Nintendo's, or are there any others you'd recommend?