צריך לקרות קריאת שמע בטעמים כמו שהם בתורה. הגה: אבל לא נהגו כן במדינות אלו, ומ"מ יד המדקדקים מחמירים בכך
One must recite the Kerias Shema with cantillation, as the Torah is read. Rema's addendum: But this isn't customary in our [Ashkenazi] countries. Nevertheless, the grammatically-inclined are stringent in this matter.
Here is a typical example of Kerias Shema as found in Artscroll siddurim ("Everyone should have a copy").
(click above to enlarge or click here)
But here is the Kerias Shema as found in the Artscroll Ohel Sarah Woman's Siddur, where the cantillation is not included "for the convenience of those who recite in the manner it is read from the Torah":
Interestingly enough, in the Artscroll "chinuch edition" siddur (Chaim Shlomo) for schoolchildren the cantillation is present (without the note explaining why there is cantillation).
Hat tip goes to Moshi.