True that OC-ing is a lot of fun but at the end, value is value and with the recent price cuts, value and performance have never been so near. At the end, why buy a $63 celeron when for $80 you get the 805 and even 3.6G out of it outperform 4.5G of the CeleronD?!
CeleronDs perform pretty well of course but as I mentioned before, the lack of hyper threading hurts too much the latest P4 cores to compete with Athlons and Semprons especially on stock performance. The exagerated 31 stage pipeline can't feed reasonably well on 256 or even 512K of L2 without HT and everyone who has a CeleronD knows it pretty well.
Besides being ~$30 cheaper than the D 805, The Celeron D 352 could potentially overclock to its 200 fsb (800 quad pumped), 4.8GHz speed using only the stock HSF, with an overclocked TDP that will most likely be under 130 watt (65 watt is the stock-clocked TDP). The D 805 clocked at 3.6GHz is more than like to need an aftermarket air cooler. 3.33GHz (166fsb) seems to be the most likely overclock on the D805 using the stock cooler (and at that speed it is equivalent to the 5GHz 356 in multithreaded apps -- more on that later). You might be able to climb higher than 3.33GHz using the stock HSF, but 3.6GHz is pretty rare; it just gets too damn hot. So, the ~$30 diffirence between the Celeron D 352 and the D 805 now becomes a $60-$70 difference when you add in the cost of the aftermarket air cooler necessary to get the higher clocks. You could always buy a D 915 instead and hit 3.6GHz with the stock HSF, but they cost ~$140, which is already ~$75 more expensive than the Celeron D 352. Do you get where I'm coming from?
M25, you also have to look at what you will be doing with your computer before you decide to purchase a cpu. If you're going to be using lots of multihreaded apps, dual core makes sense, but there are still some pretty intensive cpu tasks that do not utilize multiple cores, such as encoding using TMPGenc. VirtualDub is just getting around to using multiple cores. For ripping music, hardly any codecs are multithreaded. And of course the biggie: gaming. So, before making sweeping statements that the D 805 is better than the Celeron D 356, you'll have to take into cosideration what applications you need the cpu power for, and then figure out if those applications are multithreaded. I could make a similar statement by saying it is a better buy to get a Pentium III over a Core2 duo, and I would be right, if I was talking about processors for using microsoft word.

It's all about what you need to do.
At 5GHz, a D356 generally performs equivalent to a Pentium D 930 in mutilthreaded applications, meaning that a D 805 would have to be at ~3.33GHz to match the D 356 in those multithreaded tasks. (Do you notice that the max o/c on the D 805 using the stock HSF matches the performance of the likely max o/c of D 356 using its stock HSF? Kinda neat huh?) In single threaded performance, it takes a hyper-threading P4 at 4.5GHz, an E6400 Core2 duo, a 2.6GHz Conroe-L
😛, or an AMD A64 at 3GHz to get similar results to the 5GHz Cerlon D 356. That includes the D 805; it too would have to run at 4.5 GHz to compete with the D 356 at 5GHz in single threaded apps. You may be asking yourself why I keep talking about the Celeron D 356 running at 5GHz? Well, it's the most common speed setting that the Celeron D 356s have been reviewed at, so I'm forced to make comparisons at the 5GHz o/c. Also, it will likely be the target overclock for someone trying to o/c a 356.
Of course the biggest advantage of the D 805 over a single core cpu like the D 356 is the ability to multitask better. That is an undeniable assest to multicore processors. How much of a difference it makes purely depends on how the end user works on his/her computer. Some people do some outrageous multitasking, using burdening apps simultaneously, while others, such as myself, generally do "small scale" multitasking, where I'll generally not have anything more demanding then a couple browsers windows open, along with a Word document open, perhaps playing some MP3s in Media Player, and occasionally unRARing a file in the background. When I do my encoding work, I generally try not to use the computer; I want my multithreaded applications to use my D 805 to it's max potential.

The D 805 has allowed me to record TV while still being able to surf the net and do most average stuff on my computer without any hiccups in the video (once I set CPU affinity), which was the biggest reason I purchased the D 805 over the Celeron D 356; I use a lot of multithreaded apps, I sometimes have a serious multitasking session when recording television, and, most importantly, I'm perfectly happy with the performance of a 2.66 GHz Pentium 4 in single threaded apps (in other words, it keeps the GeForce3 Ti200 completely fed when playing games, and it's more than quick enough to surf the net and play around in Microsoft Office). What I needed CPU grunt for happened to be in completely multithread applications, so my 2.66 GHz D 805 performs like a 3.8 GHz P4 where I need it, which I'm happy with. It also doesn't hurt that my D805 is undervolted to 1.125 volts, resulting in a theoretical 58 watt TDP, which is a good thing, considering it's in an old Dell 4500 case running on a 250 watt Dell PSU. I looked at both the D805 and the D 356 for my build, and in the end after looking at what apps I was going to run with the cpu, and knowing that I wanted a cool running, low TDP processor (and being able to reuse my pc2100 ram was a plus), the choice was clear: The D 805 was the best cpu for my needs. The point I'm trying to make here is that I thoroughly eveluated my performance needs before making a decision on what to buy. I suggest that everyone should do the same when buidling their computer.
TTUL8tr, I have to study.