Let's take a look at the outfit that is left on the article.
Now, in general, this isn't too far off. I asked a friend who works for a video game company what their dress code for trade shows was like. They do wear a blazer and jeans. The main difference here is that the shirt underneath the blazer will usually be either company themed or general video game themed.
There are also a few things to keep in mind for your audience:
1) Suits are stuffy - A lot of times people will be intimidated by a suit so the only people you will see in suits are executives wanting to do business. I know I can speak on a personal level that even if someone were wearing the outfit above, I would probably be nervous to approach them because it's easier for me to know someone is 100% associated with the product being marketed and also that they may be just as passionate about something as I am.
2) Budget is a concern - While the example is just that, an example, the components cost a total of $415. If you can name me someone who is at a booth at a convention that can spend this money on an outfit without scraping by, I would be very impressed. I've found that the video game industry is based a lot on passion as well as talent.
What would I do to improve the above?
The Blazer - I actually really like this. If you think about it, it's green and silver just like Slytherin House in Harry Potter. It's a subtle nod but it is there if people look for it. However the budget issue comes into play so no matter what you do, work within that.
The T-shirt - This is something that depends entirely on the company being represented. If you're looking at a video game company that is marketing a licensed property, wearing something related to that property is a good starting point. For example, Telltale Games' The Walking Dead. That's something that you could wear either an official game shirt if provided by the company (or bought if need be according to what the company requires) or something related to zombies or the franchise.
The Walking Dead Survivor T-shirt - Think Geek
Doctor Who Bow Ties Are Cool - Hot TopicSuper Mario Bros. 3 - Hot Topic
Another thing to note about my examples are that they're fitted so these examples may not work for all shapes and sizes.
The Jeans - Perfectly fine as is. Jeans are a plus as they're casual and comfortable.
The Purse - If you're at the booth, you probably won't need to worry about your purse and you probably won't want it hanging off of you while you're talking to fans. However if you decide you want one or if you're wandering the floor, there are plenty of options out there to geek it up.
Police Box Messenger Bag - Etsy
Walking Dead Clutch Purse - Etsy - Granted as a clutch, it doesn't have a handy shoulder strap which I suggest for con goers, I thought it was a great example of a purse with a geek touch.
Star Trek Pleated Handbag - Etsy
The Shoes - They're sensible flats and a neutral color however you'd probably be just fine in tennis shoes.
In conclusion, all of these are just examples of how you can show your geeky side and still be professional. The one key thing that I like when I walk up to a booth is hearing someone who is passionate about what they are selling. If they've worked on it, if they're just a fan, that is one of the qualities that I've found comes across a lot better in the sub-culture. As Chris Hardwick often says:
It's not the things you love but how you love it.