Happy Dog was one of the first to open in the city during what I've come to know as a sort of culinary renaissance for Cleveland. Don't let the appearance fool you-- when you cross the threshold of Happy Dog, you should get ready for some awesome service, great food, and one of the best beer lists in the city. The menu is do-it-yourself; you choose what kind of sausage you want (1/4 pound hot dog or vegan italian sausage; both excellent) and whatever you can imagine to put on top of it. They have some preconstructed suggestions on the menu, but you can take your pick of the 50 ingredients in whatever combination you want. Everything is excellent quality and a lot of it is local. I recommend peanut butter, momocho habanero sauce, and peanut butter (made in house). Bacon, egg, kimchi, and chow mein is another good one. Honestly, it's hard to go wrong. Pretty much anything you throw at them is going to come out excellent. The fries are good (tots are better), but they don't stand up to the rest of the menu. You can get whatever you want as a side for your fries as well.
Bottom line? Happy Dog is the best place on the west side for great food on a budget. The atmosphere is divey, but it's clean, and the service is great. Check their schedule to see when you can catch some awesome live music as well.