Welcome aboard Sean, a Stormtrooper is an excellent choice for a costume, you can’t go wrong there, it was my first costume and still gets the most use, the smiles on people’s faces never grow old.
I would also highly recommend ‘the shed of glittering delights’ (DA props) on Facebook (now based in France), Andy is a nice person to deal with, his kits are accurate and of good quality, I guess it depends on budget, there many makers to choose from, RWA is also excellent but being UK based you have to deal customs fees and such, if money is no object then some go for RS Props, probably considered the most accurate (warts and all), to the untrained eye though (and the public) there is very little difference in appearance between all the recommended (recognised) makers though
We can give you loads of help and support here if you go for a kit to build, ready made kits are also available but will often still need alterations for a comfortable fit, personally I have built many TK’s (the name we often use for Stormtroopers) so I have a bit of knowledge in this area.
Be sure to also check out FISD detachment of the 501st, it is the ‘go to’ site for everything concerning Stormtroopers, lots of up to date info, build threads etc.
whatever you decide we are here to help and support you on your journey