I'm another home office worker, but I hate trying to work alone in most cafe's, restaurants or bars. I can't see how anyone gets anything done in a place like Ambrosia. Too much posing and social bustling, but I'm easily distracted. The Globe Cafe, in the Orrington, Evanston is a secret workplace - ghostly empty, with wifi.
A nice quiet bar during the day is a great lunch break - just about any that doesn't cater to too many daytime drunks will do. If I'm out and about and need a place to settle, I look for something without a tv - a rare thing except for some of the 3-4 more traditional Irish pubs.
In the loop, I'm more apt to head to the top floor (winter garden) of the Library - unless anyone has quiet bar suggestions in the loop.
What I often need is a client meeting place - food isn't always necessary, but a breakfast meeting is nice - Dixie Kitchen is great in Evanston - usually fairly quiet on the weekdays, Wishbone in the West loop works great for this too - and they do have WiFi.
Brother's K Coffeehouse on Main in Evanston is great - a great independent choice against Starbucks with good little food options (baked stuff and quiche-type pies). Unfortunately it's popular in the neighborhood, crowded, what seems all day, and you might get stuck with one of the tiny tables that can only fit one laptop.
I often do client meetings at Prairie Moon in Evanston - tv sound is never loud enough to be distracting and plenty of tables. They don't serve food all day though, stopping service after lunch, until 4. The Globe Cafe is another good meeting option in town.
One of the cafe's I use is Sip, on Grand, near Ogden. Good little sandwiches and a little space upstairs with a couple of couches for a spread out meeting. Sometimes very quiet, sometimes music is a bit much. During summer they have a garden, but it's more likely you'll find me across the street at the Twisted Spoke's roof garden - position yourself correctly under a table umbrella, and yes you can work on a laptop outside.
One more - Medici's in Hyde Park has dark cubby holes where no one can look over your shoulder and a fairly shaded outside patio, away from the street. Fairly quiet until the students come in late afternoonish. No alcohol.
The Globe Cafe
1710 Orrington Avenue, Evanston
Brothers K Coffeehouse
500 Main St., Evanston
Sip Coffee House & Garden
1223 W Grand Ave
Medici on 57th
1327 E 57th St