One of the things I have learned by playing Tyranids is that deployment is critical. I've played games where my opponent would get first turn and set his army up in a classic gunline and then expect me to rush accross the field through two turns of shooting. He would get a confused look on his face when i deploy nothing and say, "I'm set up". First turn he has nothing to shoot at. Second turn he has nothing to shoot at. Most time they send units out to take objectives. Then I start rolling for reserves using Hive commander for the 3+ roll and bring in outflanking stealers, DS a winged hive tyrant with gargoyle support, bring in the yealers, and other units that are designed for this type of deployment. I then focus my units on one part of the army, and deliver an (hopefully)effective first round of shooting. It is always better to throw your opponent off his plan, and make him react to you.
In looking at the codexes that have been released since 5th edition has come out, nearly every book has units that are designed to be used in alternate methods of deployment. Yes, I know that Laz/Plas wolf missle spam is a good list that is doing well in tournements. Same with Guard AV12 gun lines. You will read online right after a book is released about what units are good, and what are bad. In the example above with nids, the common wisdom about lictors and pyrovores are that they are inferior units that are fairly ineffective. Both units die to bolter fire very easily, but units don't exist in a vacumn. Now look at both units and think about target priority if there is two trygons, a podded carnifex, a hive tyrant, two unites of podded devourer gaunts (60 str 4 shots at 18"), a unit of bonesword/lashwhip warriors, and an outflanking tervigon. Target priority now becomes a little more dicey. Now a pair of lictors that get 4 str 6 rending shots at rear armor might just live the next round to charge a devestator squad. A good player will make the nids hurt in their turn, but its alot more fun and bloody then wading through two rounds of shooting. In looking at other codexes i see unit I rarely see, but think that they could be a very useful unit if deployed effectively. 3 scout walkers with auto cannons makes a cheap effective distraction unit when they are outflanked. You can even get some side shots. Being deployed from reserves means that they don't have to try and live through first turn shooting. Sniper scouts are another great unit that can be used like this.
This is just some rambling to get new players to think outside the standup and slug it out deployments, and to start using units that are considered "inferior".