Montezuma, eh?
Well to start with the three cities you're looking at already,
I would say Pella seems like your best bet, with Grinnell a close second. Personally, I would avoid Newton.
Pella has a beautlful, beautiful downtown with re-created Dutch canals, a windmill, and rowhouses. Pella probably has the most stores and dining available of the three cities, and the eastern side of Des Moines is about 45 minutes away on a four-lane highway for HD
(Menards is better) and such. Pella is also very close to Lake Red Rock which is a nice lake for boating and fishing. Downsides to Pella are...well, Pella-ites have sort of a reputation for being what we Iowans would call "snooty" and "uptight". Last I knew they had very tight building/neighborhood codes, strict blue laws, and crazy fines for tulip picking...
(don't ask)...
Grinnell is the runner-up, and not too far behind. Grinnell has an awesome college in town and more of a "college-town" feel to it. It's a pretty liberal city, but very friendly and clean. They also have a good hospital in town, along with lots of stores and dining. Grinnell is right on I-80, so it's easy to get to Des Moines for things. Downsides to Grinnell are a lack of outdoor recreation and it's location in the relative middle-of-nowhere.
Something else to consider is Williamsburg to the west of Montezuma. Williamsburg is a much smaller town, around 3,000 people. It's very much the complete "small-town Iowa" experience, with lots of mom-and-pop stores and a turn-of the century town square and the like. However, unlike most small towns...it's growing instead of shrinking--since it's becoming sort of a bedroom community to Iowa City. You'd be about 40 minutes from Montezuma and about 40 minutes to Iowa City, which is the cultural hub of the state. Iowa City also has all the big-box stores that you're looking for.
P.S. We don't have Meijers in Iowa. We have Hy-Vee...which is pretty much the same thing.
