Just as a small geography lesson, Starfish is located out of Lantana/Lake Worth area, just before the Lantana bridge, if I recall correctly.
The Palm Beach Ocean Inn is a piece of Florida Nostalgia...I've done drinks there, but not stayed. It's an old 50's/60's era hotel, and it's got it's own fan base, though I thought I'd read that it was finally sold for condos. I'd guess for right on the water in that immediate area, it's going to be the cheapest you can find.
Right near the Lake Worth bridge area is(was?) also a Howard Johnson's (though it may be long gone), and on the ocean side, a Hilton. For waterfront, most of that area is purely residential, if you're insistent on being on the water.
The Gulfstream Hotel is a boutique hotel in Lake Worth, right on the intracoastal, recently taken over by a Marriott/similar-named franchise that may be in the affordable range.
Hmm, romantic on the water. For on the water (ocean) you may have to head up to Palm Beach-proper, @ 15 minutes. Charley's Crab is very nice, though not cheap.
For romantic-eclectic, (not on the water or even a romatic location),
Bizarre Avenue Cafe is a unique experience...think tapas and wine, couches and cocktail tables instead of standard table and chairs. It's considered THE first date restaurant....
For Florida-kvetch factor,
the Key Lime House is great for drinks....I believe the Starfish is docked right behind it.
For a VERY yummy breakfast, there is a well known place on the Lake Worth Pier (of course, the name escapes me right now), and a place on US1 (the "mainland" side) called "The Friendly Greek" that is very cheap, too.
Feel free to PM me and I'll try to rack my brain for more specifics (I used to work at the Four Seasons just down the road and knew all the places to send guests....it's just been a while).