The whole AMD vs. Intel debate comes up quite regularly, and it always will. That's because at its core it is a huge part of deciding what is right for your computer needs. Regardless that everyone will have an opinion, and that indeed some hardware will be better than others, the fact is that technology changes quickly. This means that it is GOOD to discuss this because not only does it help to discuss both sides of the story clearly, but it is relevant to address this through time as technologies advance together.
Now, I've always liked AMD. We had all AMD workstations for several years and had wonderful luck with them, and I still have several AMD computers at my own computer business. For many years they provided a level of performance at a price that Intel just could not match, so if you wanted a quad-core processor for cheap, AMD was your way to go. If you were interested in only the fastest and the price didn't matter, then AMD probably didn't fit your bill.
That being said, I have not built an AMD-based system (for myself or any customers) in almost a year. The simple truth is yes, Intel is leading the performance capabilities when it comes to processors. With the release of Sandy Bridge, the performance that could be had even in their cheapest processors was more than anything that AMD could offer at the same price point. It was at this point that AMD lost its price advantage over Intel, and since then they really have taken a hit. Bulldozer was kind of their last ditch effort at rebuilding and making a huge comeback into the desktop processor market, and unfortunately it fell short. In fact, in some ways older Phenom II X6 processors were faster than the newest flagship AMD FX-8150 even though they were lower clock speed and fewer "cores".
After years of having a noticeable market lead over AMD, many technology designers have begun basing their software, their requirements, and their recommendations on Intel platforms and technologies. Because of this some software and drivers on the market have been specifically fine tuned for Intel systems and thus perform better on Intel than on similar AMD platforms. This is part of the reason why so many of the big name computer brands out there like Dell and HP push more Intel systems for their business lines than AMD.
AMD recently announced that they were, in fact, calling it "quits" on trying to beat Intel at the desktop processor market. For the first time, AMD was admitting they were just too far behind Intel. Instead, they will be shifting the majority of their focus to mobile processors and server processors where AMD still has a price and performance advantage over Intel in several ways.
Now, as to the original question for this thread. I've built numerous systems using the Intel Sandy Bridge platform and have been incredibly pleased with the performance, stability, and value that these systems offer. To get the best value and performance you can for your money, though, takes a little bit of knowledge beyond just what components are compatible and aren't. That's why unless you are confident in your own technical skills I'd recommend you contact a professional system builder for help. I know that Casey at Signburst Computers knows his stuff, he's incredibly helpful and knowledgeable in computer systems specifically intended for the sign industry, which many computer builders are not.
If you can assemble a computer confidently, or have someone you know and trust to do it, then you can save yourself some money but you will have the additional tasks of assembling the system, installing software, drivers, etc. and ensuring it is all running properly. For a design system I would recommend a computer based on the Intel Sandy Bridge LGA1155 platform. Before I can help you out in more detail, though, I'd have to know what kind of performance expectations you have as well as what budget you have to work with. After all, while you can get quite a powerful computer for $1,000 today, there's a huge difference if you instead wish to spend $2,000.
If you are only wanting to look into a pre-built system from the big names like Dell or HP, I'd never recommend using a consumer grade computer for business usage. I've spoken directly with Dell support staff several times and I can tell you they do not build their home computer lines with the quality or performance intended for continual business use. There is a difference in a Dell Precision desktop costing $1,500 and a Dell XPS desktop costing $1,500. You are looking at better warranty service for one, but also hardware that is intended for continual daily business usage and higher efficiency. This is especially noticeable when comparing consumer and business laptops, which is why our computer business does not order any consumer laptops for customers and only ever recommend business grade laptops.
Again, while we have heard your intended usage for this computer, there's still some additional information we need to further assist you with your computer needs. Of course the primary question is what kind of budget you are looking to spend. For instance, are you looking to get the best computer you can for under $1,000 or are you more interested in just getting the best system you can so long as its somewhere under $3,000?