IIRC, Ford and Nissan's current hybrid technology are licensed from Toyota. I don't know about the current Altima Hybrid, but the previous gen, I read the display was nearly identical to Toyota's. Hopefully the recalls, slide in sales, along with the bruising will get Toyota going again. Toyota is reminded of being the hare in the race with the tortoise.
Toyota has dumped $50M into Tesla that might be the answer to the LEAF and Volt.
Ford Fusion Hybrid (and twin Mercury Milan and upscale Lincoln MKZ Hybrid) is a major thorn on Toyota's side...the FFH gets better mileage than both Camry Hybrid and Lexus HS250...and can go further on battery power. (The last part is controversial because Ford abuses the NiM battery more than Toyota...possibly at the expense of durability down the road. Regardless, though, Ford gives the same warranty as Toyota in regards to its hybrid components.) FFH's hybrid system is PURE Ford...even though the basic concept is very similar to Toyota's system. Basically, it seems like Ford bought the Toyota Hybrid system and made it better for themselves.
Nissan's hybrid system currently in the Altima is pure Toyota. However, the upcoming Leaf and Infiniti M35 Hybrid system is pure Nissan i believe.
I think that the above two are more of a threat to Toyota than the Chevy Volt. Volt is nice and all, but it costs too much while providing too little (in luxury).
As for Lexus, my parents just bought a 2010 Lexus ES350. In the past, i have always discarded the ES as a tarted-up Camry...and always wondered why people don't just buy the Avalon because it is the same price as the ES but it is bigger, more stuff, and has a very good JBL sound system. I have changed my mind. It is actually a pretty nice car, a bit expensive for what you get, but a nice car nonetheless. I can now see why it is so popular. It is (for 2010) handsomely conservatively styled, quiet, very comfy, and (for 2010) has a very nice upscale interior. Maybe i am just getting old in my head and this is why the ES appeals to me?!

My biggest problem with it is that the base stereo system is kinda sucky...esp. when you consider that the Camry JBL system is better for much less money.

And the Avalon JBL blows the ES base system away by a mile!
The car that i see has fallen really really behind is the GS. The styling is getting old...in fact, the current style got old rather quickly. Performance is no where near the class leaders.
Uneek, check out the 2011 Jaguar XJ. I made the mistake of looking at it in the showroom floor...WOW!! The styling is daring and attractive...and the interior (at least at first glance & touch) is uber classy...i would say even class leading. The LS interior doesn't hold a candle to the new XJ...and i would venture to say that the XJ interior is both better styled than any Lexus and the materials easily match (& beat??) that of any LS! Yeah, i know that Tata Motors own Jaguar and that past reliability/durability history just sucks...but, holy cow, the new XJ is impressive. I am dying to test the Bowers & Wilkins 20-speaker stereo system in the XJ...and compare it with the Lexus LS Mark Levinson Reference system...however, i think that this is where Lexus LS will still remain the class-leader.