My X58 had better not die, X58 for life, or until it dies :(

Its unbelievable how good the I7 / I5 CPUs were, even the first gen ones are still going strong.

Here is a nice benchmark chart with the current price points on the right edge. The fastest i5 on that list (Intel Core i5-4670K) is faster than some of the i7s. You can run around that site to get a feel for benchmark versus costs on many pieces of hardware.
 
I have become a huge fan of the Sandy/Ivy bridge design, specifically the K models on the right motherboards. Out of curiosity, I used their PassMark's software to benchmark my machine recently and my CPU (i7-2600K) came in at 10919, which way outshined their benchmark (8559), and I have mine set to "power saving mode" and runs cool as a cucumber!

From checking in the performance monitor, X3 doesn't seem to be very multicore intensive, but I only had 4 tracks running together. There's very little out there that gains any benefit from hyperthreading, IMO I'd only bother getting an I7 if you are going to get one of the hex cores, otherwise stick to an I5.

 
Go Xeons !
 

Thanks to everyone for the advice.  Sorry about the signature and the delay in getting back to the post.  I am running a fairly old computer tech wise so I know I will get a big performance boost no matter what I go with.  Just trying to make the right decision for extending the machine as long as possible.   I basically am a hobbyist singer\songwriter so recording\mixing power not a great need at this time.  Was just trying to save a couple of hundred bucks to apply to a new acoustic guitar upgrade.
 
I did finally find this comment in an article on the Cakewalk site that seems to indicate that Sonar does utilize Hypertheading which I don't believe is implemented in the I5 processor is I am understanding correctly.
 
Hyper-Threading - If you have been working with computers for awhile you might recall the initial implementation of Hyper-Threading on Intel processors. A very powerful enhancement at the time, Hyper-Threading has been improved for the i7 processors now making twice as many threads available to the Operating System. Simply, the quad-core i7 processors look like octo-core processors to Windows. This is extremely powerful for multi-threaded applications such as SONAR which can take full advantage of every thread available.
 
Tried to add to my signature but not sure I got it done until I post this.
Thanks,
Terry

Gonna post my Specs here and it will probably show up in the signature line this time.  I must be doing something wrong.
 
Windows 7 Home X64 SP1, 2.4 Ghz Intel Core2Quad, Intel DP35DP, Cakewalk Producer X3d, BIAB 2014, Varranger,Tascam US-1800,Mackie MR5 monitors

Hyperthreading is being over hyped here.

While it looks like you have double the cores in windows, there's still hardly anything that is programmed to use them, and they are even harder for software developers to utilize than actual physical cores.

I wouldn't rate hyperthreading as a must have feature, look for which CPU is faster as a priority, and not just based on clock speed but check reviews, then secondly look for more physical cores.

The time to buy an I7 quad core is if you can afford to buy more than an I5, but don't want to pay more for a hex core.

An up to date quad core I5 CPU is no slouch, and oftentimes outperform I7 CPUs because HT isn't supported by the application in use, and due to not having HT, they run much cooler and can be clocked higher.

When I built this computer, the first 6-core processors were hitting the streets and this article was where I based my decision (that and I was dead set on an ASUS motherboard due to their architecture and early adoption of USB 3.0). If you jump to the conclusion (page 13 of that article), Intel sort of burned themselves by releasing a 6-core, expensive design while also updating the Sandy bridge architecture. At that time, most software was not even scripted to use all cores, so having 2 more was a waste (with the exceptions of video/encryption software, in general). The bottom line was that the only thing "Extreme" about the 990X was "power consumption and cost."
 
For a DAW, the Sandy/Ivy bridge designs are more than adequate for just about everything (SONAR is scripted to use all threads available quite well as your quote implies). Before any purchase, be sure to research things and ask a lot of questions.

I'd have to search for benchmarks, but I don't think audio programs kill the CPU, it is more about the RAM. That and get an AWESOME interface.
 
I bet if you had a very efficient audio interface and max memory (32GB or 64GB on the newest boards) with new drives, that an i5 would work just fine for MOST of us.
 
That said, I have that old i7950 :P

Different plugs and processes affect RAM and CPU differently, it's easy to max out both or either if you would have a mind to.