I too like the Sentinel class. I use a custom .ini file that allows me to use all the guns so a soldier is wasted, I prefer the powers anyway. I do have a few Adepts, Engineers and Vanguards to shake things up.

__________________
My Gallery
Hall of Torque
Mass Effect1 & 2

Only ever played as a Vanguard, and I have never regretted that decision I made 4 years ago in ME1. Thats bearing in mind that I dont think the Vanguard class reached its prime until ME2. Prior to that, the lack of armor/weapon choices and the comparatively poor Biotic powers did kinda restrict your gameplay style, but I learnt to adapt. I think that made me a more versitile player when in ME2 you end up with more weapons and better powers. Thats actually how I'd describe the Vanguard in one word; "Versitile". Especially since in ME3 you have access to all the weapons.