SD-quality graphics are designed for SDTVs, at least in my opinion. In HD, most of my Wii games look horrible.

The games that are can support 480p look good on 42" HD TV. Not sure common they are tho, Excite truck and Mario Strikers are the only ones I can think of straigth away. Wii sprots doesn't look all that good tho.

SD content looks bad on most HDTV, except RP ones (LCoS, DLP, ...). That's because of how they display the image, only RP is near the methods used in theaters, which is closer to the look of SD (softer image). Besides, SD content shows all the defects HDTV have, and the LCD and Plasmas have MANY artefacts and defects, due to the technologies used. SXRD is the technology with the less artefacts for now (but the crown in image quality still goes to plasma).
I replaced my old 52" SDTV (Rear Projection) with a 55" SXRD (RP too) and the SD content now looks BETTER than on my old display. There are two catch though :
- it looks better after calibration, it looked worse before (silk screen effect reared its ugly head immediately). HDTV all comes with default settings that are made to capture your eyes in stores, under neons and the like, delivering a very bad image fidelity, and unbearable to stare at for long.
- I have the european version, which comes with the better engine chip (MFC 2.5), while in the USA, most comes with the 1.x version. The chip does all the deinterlacing and scaling, for example.
Well, this TV is plain amazing, as I didn't think I would say one day that a HDTV would look better than a SDTV for SD content.

But what will be the most annoying, is NOT the image quality. I don't know the Bravia LCD (as I have a Bravia RPTV, which isn't the same thing), but I hope it has a game mode (I think it has). If not, the Wii will just be unplayable, because of the lag induced by the TV.

Legend 11 I highly reccommend u buying 4 ur Mom Warioware Smooth moves, Mario Party 8, Rayman Raving Rabbids, or Excite Truck great games 4 casuals/familes

I use my wii on a HD TV 1080i/720p panel. It's a samsung. The grpahics look pretty sweet too me. Samsung have seem to combatted the annoying jaggies on their LCDS. Scary thing is new revised models with double contrast ratio fast response times and higher brightness are coming. So they will look even better.

ATM i'm using it as 576i as well which im suprised looks good. Will be getting a component cable later in the month to switch to 480p.

I use Wii component cables for my 42" Plasma, it looks great, you can definitly see a difference before hand when I didn't have the components.

I have 56" Samsung DLP, and the Wii looks fine even with composite. However, I have upgraded to component, and yes the picture is more crisp.

So is the upgrade worth it? Yes.
Is it absolutely necessary? No.

If its a choice between buying your Mom a 2nd controller or a game or the component cables -- get the controller or game.

no jaggies on my 42" samsung plasma, I use component (big upgrade as far as picture clarity)

Some HDTVs have better scaling chips than others.  My set has a particularly good scaling chip (HLS5087w).  It's a 50" 1080p set and I connect my Wii via component cables.  The component cables made a huge difference.

it looks great on my sharp aquos 720p 1080i 32 inches with component cables@ I think that the bigger ur tv the worst sdtv looks on it