Between the 3 calibers you mention I'd say you've made the right choice.
If it was punching paper you wanted to do I'd advise to go with the .223 for economy. But since you want a gun that can take whitetail and perform other tasks as well, the .243 is the best of the 3 you mention.
BTW, Michigan does have caliber limits for large game / deer firearms.
The rule staes that
"All Firearm Deer Seasons - Rifle Zone
[font="arial, helvetica, sans-serif"]In the rifle zone, deer may be taken with handguns, rifles, bows and arrows, shotguns and muzzleloading firearms including black powder handguns. It is legal to hunt deer in the rifle zone with any caliber of firearm except a .22 caliber or smaller rimfire (rifle or handgun). Crossbows are legal to use by a person 12 years of age or older during the Nov. 15-30 firearm deer season.
Exception: See Muzzleloading Deer Seasons above for restrictions during this season."


[font="arial, helvetica, sans-serif"]Good luck with your purchase.
[font="arial, helvetica, sans-serif"]Have you decided on the manufacturer and style yet? The Savage packages are touch to beat now that some of the models can be had with the Acu-trigger, and the dual pillar bedded action. I'm not sure biut some may also be available with all of the above AND the detachable mag and/or hinged floorplate. However, these extra nice features are not included in the cheapest of the bargains from Savage.
[font="arial, helvetica, sans-serif"]There are a lot of nice rifles out there for you, and depending on your wallet, you can get almost anything you want.