The design of the website (or web application) is a very important element in web development regardless of the choice of a web platform. Whenever a user comes to a website, the very first assessment of how the good the site is depends on how good it looks. As we know from real life, appearances matter quite a lot. Having a good personality is also crucial but looking good is always a good start.
Of course there is also this big topic of functionality and a web application that looks nice but does not work the way the user expects or perceives as logical will not score that high on user satisfaction charts. However, functionality is more of an issue for web applications and not as much for websites, for the reason that vast majority of sites on the Internet are to be some sort of a brochure for a company, or a collection of information pages and thus their functionality is rather simple and typical.
Naturally, there are also large corporate sites with a vast number of pages where functionality of a site suddenly becomes important and making the information easily accessible becomes a big priority for a web developer. But for those companies whose main area of business lies outside of realm of IT services (or e-commerce), a website is more of a large billboard poster letting the world know about the company's existence. A lot of stress in this kind of web development falls onto making the website attractive while the functionality remains standard across as for any other site.
Web Development with Bespoke Design
Some years ago the only way to design the look of a site was to code it in straight-up html. In essence, every web developer was also a web designer at the time, in fact some still use those two terms interchangeably. They are not the same though: a web developer deals with the coding part of building a website, while a web designer devises the look of it. By trade a web developer would most commonly be a programmer, while a web designer would often have graphic design as their main area of specialization.
It follows that if a client needs a new website, they are essentially looking for two things: to design the look of the new website, as well as have the site built based on this design. As we see, that involves two stages, designing the site, and implementing it in code. With both processes being rather time consuming the client would have to pay for the hours that the website designer puts into their work, as well as for the hours that the web developer spends on actually implementing it.
This approach is how custom designed sites are implemented. It ensures that the site is unique and there is no other site that looks like it. However, some question this approach since when everyone is trying to look special as the result no-one really does. At the end of the day, all Facebook and Twitter profiles have identical design and nobody complains, while MySpace allowed customization of user profiles, and frankly, the whole service ended up looking like a mess.
Of course we would not go as far as to suggest that every single site on the Internet has to use the same design as Facebook profiles do. The reason for this comparison is that this is where stock templates come in, which is a very common way to develop websites and web applications nowadays.
Web Development Using Stock Designs
Some time ago web developers and web designers started to realize that not all clients care that much about standing out as much as possible, all they care about that their website looks decent and the cost to develop it is not too high. With this in mind some graphics designers started to build generic design templates using standard browser html and css technologies and sell them on to web developers who would customize them and use them to develop actual sites.
This approach has been working very well for everyone: clients could get a new site developed cheaper and faster as there wasn't as much graphics design overhead anymore, web developers did not have to spend quite a lot of time on a fairly tedious task of manually converting the Photoshop design into a proper html code. Graphic designers liked this approach since they had an additional income option of selling their designs online to addition to their regular work.
These stock web design templates used to be somewhat expensive years ago, costing in the range of several hundred for a license for a single site, which was possibly a remnant of web design being generally a domain of custom projects. Nowadays due to fierce competition they are much more affordable now and their cost can be negligible in the overall scale of a web development project budget, however there is normally some customization time and expenses involved.
As a client you do not really have to burden yourself with a search for a specific template, the easiest way could be to let your web developer find out about your project requirements and then research and present potential options for the project. With that said, some clients like to be more proactive, so if you'd be so inclined you can have a look at one of the outlets used by web developers to source their designs at templateforest.net. This is possibly the most widely used resource of the kind currently.
A word of warning should follow though: using a stock template does not mean that there is no overhead on the design part whatsoever. It does not happen very often when a client's requirements transpire to a specific template exactly and more often than not some time is required to modify and update the template to suit the client's needs. Sometimes amount of work going into a template upgrade is so significant that a web developer ends up with a brand new design at the end, however there is normally still some saving of time compared to designing a website from scratch.
This work also addresses a concern that some clients would have of the site looking like other site: the fact is that the amount of updating that normally goes into a specific site during the web development process is such that the issue of the site looking like some other site on the Internet is not really a problem any more. With that said, if you believe that a specific thematic template looks and is structured exactly as you think your site should look then indeed there could be certain savings made during the web development.
Overall it could be concluded that both options are viable during web development. In fact both approaches could be combined in a timed manner: a client may want to have a website developed using a stock template initially due to budget requirements, or simply because they are not sure exactly what they are looking for, and then later go for a facelift of the website using a bespoke design. Whichever approach is chosen though, the most important thing would be choose the right web developer.