Seems to be the best rate around from a reputable bank. Also, appears that you can link it to an ATM card which is pretty cool for an online savings account (ING and Emigrant do not offer this feature).

• HSBC Raises Online Savings Rates to 4.65%
• HSBC Online Savings Paying 4.8% APY
• HSBC Online Savings Now 4.25% APY
• HSBC 4.0% APY, ING Direct 3.5% APY
• New Higher APY’s!