lots o' questions....let's see if I can give you lots o' answers.
first, I've gotta say that I don't think the perfect PMP exists. they all have flaws somewhere, so if you're waiting for something without any shortcomings you'll wind up with nothing.
now, for my needs, the TAO comes pretty close to perfect. some of the features are both simple and brilliant, like having everything on the external SD card. why? because (1) I have yet to see a PMP that seamlessly integrates internal and external memory so better to have everything in one place, (2) SD cards are the cheapest, and (3) it is literally impossible to brick a TAO with a bad firmware upgrade -- just yank the SD card, reformat, put new firmware back on, and you're in business.
also, whether I happened to get lucky or maybe SmartQ worked out the bugs, all I can say is that my TAO is almost flawless. it has a couple firmware issues that still need to be worked out, but the unit itself is top notch quality. and as to your T5, it sounds like you have a problem with your battery...maybe because of over-charging or maybe because it's just old...or both. anyway, it shouldn't run down this fast. FYI, if I am going on a long flight and need extra long video time, I use the Tekkeon MP1550 external power supply... you can pick one up for about US$17, pop a bunch of rechargeable NiMH AA in it, and you're good to go for hours....or days of audio.
as to your question about album art, I'll play around with the TAO and see if I can answer your questions. I don't know off hand because I myself never use it -- videos I watch, MP3 I listen to...personally, I don't care about album art because when I listen to music the player is closed in its case and in my pocket, but that's me. I will say that the TAO firmware overall is a real pleasure...very well thought out, very flexible.
as to pricing, the TAO is priced higher than a lot of other PMPs, but you can't compare it to the M8...the M8 is a full blown phone, and will cost at least 2X the TAO. different products entirely. and as a PMP, I would take the TAO even over main stream products like the iPod Touch for too many reasons to go into here, but the biggest ones are the TAO's superior codec support and external memory.
to anyone who wants to watch xvids without any converting, my advice is to forget PMPs and get a netbook...but, again, this is a totally different product category. even with the ADI Blackfin chip....which is screamingly fast for a PMP...you're gonna want to convert to avoid jerkiness. video just takes a lot of brainpower to process, there's no getting around that.
the only remaining bug I've found on the TAO is the minute audio hiss, and again, it really depends on your use as to whether you will even know it's there. if you're like me and you use your PMP on trains & planes, no, you never will, because the environment is too noisy. and for these settings the sound on the TAO is actually great...very punchy, very tight. but if you're someone who's gonna say "hey, this thing can play lossless audio formats and I've got some high-end earphones" and you're gonna sit down in a quiet room and really LISTEN to your music, then on quiet passages you will hear the interference. so I discovered the problem but it doesn't bother me so much as it annoys me that SmartQ didn't design it out.
all in all, I've been impressed & pleased with the TAO. for my purposes, it's just about perfect. if you DO get a TAO, a PERFECT case for it is the Lowepro DMC-Z, which you can pick up for around US$10. get this case, cut out ALL the inside pockets, stick a piece of velcro on the back of the TAO and the other piece inside the case, and you're all set. the case is padded but snug, and if you use this you won't need a screen protector.