Sassyangies, I am totally with you on loving full-fat lattes. I work as a barista and can have my way with free coffee and espresso drinks (AH!), which is a perk but also is so tempting and tests me most every day I go into work.
Anyway, lattes will definitely be more calories than a regular coffee because of the majority of the drink being milk. Like others before me mentioned, you can try flavored coffees which have a less intense flavor than darkly roasted black coffees, which is usually what people think of when thinking of plain coffee. Flavored coffees can actually be quite good! You can add fat-free half and half which will give it a bit of creaminess and some Splenda too. Also, a perk is that regular coffee is always cheaper than espresso drinks like lattes.
If you MUST get a latte, I recommend going to someplace other than McDonald's. If you go to a coffee shop designated for coffee specifically, they are likely to know more about the drinks they're serving you and will also have more sugar-free flavor options (chocolate, hazlenut, caramel, irish cream, etc.)! Also, you might try a café au lait (half coffee half steamed milk) and add a bit of sugar-free syrup, or if you really are trying to cut back on the calories caused by the milk, try an americano and add some sugar-free flavors in, then just a splash of fat-free half and half. Then again, I always think that if you are going to get an americano you may as well just get a flavored coffee because it will be less expensive.
Honestly, like Dezzie said, the plain taste of espresso or coffee is something your palate will just need to get used to, but it will be worth it once you notice a change!