Here's the thing... does money really matter to you? If money matters more to you than your happiness then wait. If you'd rather be happy now then buy the game now.... of course this really applies only to those games you KNOW you'll be happy with. If you're not sure, then wait..
As an example, I recently bought Rocksmith 2014 and a week after I bought it, It went on sale (It was only about $10-$12 cheaper). I kinda wanted to kick myself for not waiting for a sale, but at the same time I got to play the game for a week and it wasn't like the game went 50% off so it's not so bad.
They DO have spring sales lately, but they're minor events compared to the summer and winter sales. If you can wait about 6 more weeks they'll probably have a sale but it's not guaranteed that you'll find the game you want on sale.
You can go there to see a price history of any game on steam and use that to gauge how much you could save by waiting.
Personally, I only purchase games when they are in bundles or 75% off or higher most of the time, since sales are so frequent. I have a pretty big backlog and I tend to buy a lot of games during major sales. At the rate I buy games, I will eventually run out of stuff to purchase that interests me, so it doesn't seem worthwhile for me to purchase games at full price.
Exceptions to this would include if there is a new release out that I really want to play and know I'll get a ton of hours out of and games which never seem to go on sale.
Unless you're going to play them all and beat them ASAP, I would just buy one or two of the longer ones and wait it out. Should easily keep you busy until someone (Amazon, GMG, Steam) has a sale. Also, check GMG right now. They have a 20% off code if you spend over $10 and they sell most games as Steam keys.