Out of those two choices it's be a lab, I heard too many 'bad' things about beagles. By 'bad' I mean traits that might make them brilliant for someone who knows what they're doing and wants to put them to work, but would likely make them a nightmare to live with.
I agree with Archie though - lurchers make excellent pets. Obviously it's not a breed so they're all different but generally speaking they're fit, healthy, brilliant with people and very loving, and will do as much exercise as you want.
We've got a whippet x saluki/grey and she's wonderful. Only problem is her chase instinct which isn't too hard to manage with a bit of care. She also hates dogs she doesn't know but that's because she was attacked by some sort of massive wolfy/akita looking thing when she was young which could happen to any dog.
She's happy with a quick raz around the field or a 12 mile walk in the peaks. Not the brightest bulb in the box though - they're never going to be obedience champions!
For the record - we have most issues with small, yappy dogs. Border terriers and that sort of thing. Never come across a bad staffy, mastiff etc but the numbers of nasty, badly behaved and un-managed small dogs are ridiculous.
I appreciate that some dogs have issues/problems, it's how you deal with it as an owner that matters.