Do people speak Spanish in Argentina?

On a 4-month tour of Latin America, one of my friends arrived in Buenos Aires after spending a month in Mexico, and came to the conclusion on the first day "I guess they don't speak Spanish in Argentina." True, the Spanish (castellano) spoken in Argentina is so different it literally seems like another language. Here's some things to keep in mind language-wise on your trip to Argentina:

• Accent: The biggest difference with the Argentine accent is that "ll" and "y" is pronounced as "sh", so yo me llamo becomes sho me shamo. There's also a very distinct rhythm/cadence to the language that is different from any other Spanish speaking country.
• Gestos: One result of the early 20th century Italian immigration to Argentina is the extreme gestures Argentines use to communicate. My favorite: saying ojo and/or pointing to the eye to say watch out or bringing all your fingers together and moving them slightly apart and together several times to indicate being scared (apparently signifying your butt muscles clenching in fear when you're scared -- I didn't make that one up).
• Saludos y despedidas: The typical greeting goes a little something like this.
  Guillermo: Hola, buen día. ¿Cómo andas?
  Pablo: Todo bien, por suerte. ¿Vos?
  A typical goodbye: chau, suerte.
• Vos: Argentines don't use tú when talking to their friends, they use vos, which has its own conjugation. For visitors, you'll be understood if you use tú, but be aware that vos exists. Argentinos seem to use usted much less frequently than in places like Mexico, especially in Buenos Aires.
• Jerga: Slang. The Argentine vernacular is so full of slang it has its own name (Lunfardo) and dictionary. A few favorites:
• che: used roughly as hey in an informal conversation, a word that Ernesto Guevara used so much Che became his nickname.
• boludo: often used in combination with che, can be an insult or an informal greeting, so best not to start using this one on your own.
• pelotudo, caradura: are both insults, roughly the same as jerk.
• quilombo: ¡Qué quilombo!: What a mess!
• Food and ordering: A typical breakfast in Argentina is a café con leche or cortado (espresso with a few drops of creme) and medialunas (croissants) or facturas (pastries, but ojo, factura can also mean receipt). Lomo (steak) is a delicious staple that can be ordered al punto (medium) or jugoso (rare). Water is served from bottles with the option con gas (mineral water) or sin gas. To order draft beer, ask for cerveza de barril. Other things to try:
• alfajores: a soft cookie filled with dulce de leche and generally dipped in chocolate.
• helado: thanks to their Italian heritage, Argentines make delicious gelato-style ice cream. Some good flavors: anything with dulce de leche, sambayón.
• empanadas: most Americans are familiar with these, but Argentine-style empanadas are particularly delicious, especially jamón y queso and margarita (basil, cheese, and tomato).
• provoleta: grilled provolone cheese topped with olive oil and herbs. Was this idea crafted in Wisconsin?
• Nicknames: Argentines love a nickname for people they barely know, including gordo, flaco, negro or, perhaps more often to the ladies mi amor, linda, guapa.